Stainless steel lunch boxes, rated on what they’re made of

• “BPA free” on a box with no polymer in it is a non-claim. There is nothing in this product for BPA to be in. Its presence suggests the phrase is on the page for reassurance rather than information — the same empty sentence Thermos and Hydro Flask put on steel. [1]
• Explicitly not leakproof, and it says so on the product page. Full marks for saying it; it rules the box out for anything wet, which is most of what parents want a compartment box for. [1]
• The only lunch box in this category with a published oven temperature — usable in the oven up to 200°C. Nobody else gives a number. [1]
• Priced in GBP with UK-focused shipping. A US buyer’s landed cost cannot be determined from the maker’s site, which is why it sits here as a benchmark rather than a recommendation. [1] [2]

Sources (2)

1. Elephant Box 2L product page
2. Elephant Box classic lunchboxes collection

• “18/8” is an alloy family, not a grade — 304, 302 and 305 all satisfy it, with different corrosion behaviour. OmieBox and Elephant Box on this page both name the actual grade. [1]
• Explicitly not leakproof: “we recommend packing dry foods only”, stated on the product page. Good disclosure, hard constraint. [1]
• Neither a warranty nor a country of manufacture is published. The terms of service carry only a blanket disclaimer that the service is provided “as is… without any representation, warranties or conditions of any kind”. [2]

Sources (2)

1. LunchBots Small Snack Packer product page
2. LunchBots terms of service — the blanket warranty disclaimer

• A straight contradiction between two of their own pages. This 304/18-8 box: “this product is made of steel and CANNOT be used in the microwave”. Their Meal Prep Box Set, also “stainless steel (304/18-8)”, is sold as an “innovative microwave-safe steel box” rated to 1000W. Same maker, same alloy, opposite instruction. [1] [4]
• The warranty excludes the headline feature: the box is sold on being “100% leakproof”, and the silicone seal that delivers that is covered for two years rather than the lifetime the steel gets. [3]
• “BPA free” on an all-steel, explicitly plastic-free product. It was never in question. [1]
• No silicone standard and no country of manufacture, on a site that is otherwise one of the most material-literate we have read. The About page places only the design studio, in London. [1] [2] [5]

Sources (5)

1. Black+Blum Stainless Steel Lunch Box Large
2. Black+Blum — our materials
3. Black+Blum lifetime guarantee — the two-year silicone carve-out
4. Black+Blum Meal Prep Box Set — the contradicting microwave claim
5. Black+Blum about page

• No third-party testing, certification or Prop 65 statement published that we could find. [1]
• No country of manufacture stated on the product page, FAQ or warranty page. [1]
• Not leak-proof. LunchBots’ own advice is to pack dry foods only. [1]
• Lifetime warranty against manufacturing defects, which is generous for the price. [2]

Sources (2)

1. LunchBots Large Cinco product page
2. LunchBots warranty terms

• Grade 201 substitutes manganese for nickel and corrodes more readily than 304. Committing to one grade, or labelling it per product, would cost nothing and would raise this score several points. We have asked them which one ships in this product. [2]
• No warranty published anywhere we could find. [2]
• No lead or metals testing published. [2]
• No gaskets, so not leak-proof. Their separate Splash Box is the leak-proof one, and it seals with silicone — worth knowing if “plastic-free” was the whole reason you were buying. [1]

Sources (2)

1. ECOlunchbox Three-in-One Giant
2. ECOlunchbox FAQ — the “201 or 304” disclosure

• No third-party testing, no certification, no Prop 65 statement. [1]
• No country of manufacture stated on the product page or the FAQ. [1]
• The second claim — “made without PVC, phthalates, lead, or vinyl” — is on Bentgo’s FAQ rather than the product page. [2]
• The 5-year warranty is well above Bentgo’s own stated 1–2 year baseline for most lunch products, which is a decent signal about the line. [2]

Sources (2)

1. Bentgo Kids Stainless Steel Lunch Box
2. Bentgo FAQ — the wider “free of” claim and warranty baseline

• The product page hides the plastics behind “food grade plastic” while the FAQ names ABS and PP. The page a shopper actually reads is the less specific one, and ABS is not a resin most parents expect in a food container. [1] [2]
• “Food grade silicon” is used as though it were a certification. No agency issues one. Neither LFGB nor FDA 21 CFR 177.2600 appears anywhere on the site — and in fact appears on no lunch box maker’s site we read. [2]
• Handwashing is “best” but the site never says the box is not dishwasher safe. Ambiguous guidance on a $50 product whose steel thermos and ABS shell have very different tolerances. [1] [2]
• Credit: country of manufacture stated plainly — “OmieBox is responsibly made in China”. [2]

Sources (2)

1. OmieBox product page
2. OmieBox FAQ — the full material list and country of manufacture

• Marketed under “Stainless Steel Bento Boxes” when the outer box is PP. A buyer scanning the category name would not get that. [1] [2]
• Two of kinsho’s own pages contradict each other on care: the product page says “easily wash the outer box and silicone seals by hand”; the collection page says “bottom box and tray are top shelf dishwasher safe”. The warranty then excludes dishwasher damage to non-dishwasher-safe parts — placing the risk of that ambiguity on the buyer. [1] [2] [3]
• “Japanese grade” describes the standard, not the country. It reads as an origin cue and is not one; origin is unpublished. [1]
• The warranty runs from “6 months to 2 years” depending on the item, and you must find which from the printed instructions rather than the website. That is the shortest floor in this category. [3]

Sources (3)

1. kinsho mini steel bento product page
2. kinsho stainless steel bento collection — the conflicting care advice
3. kinsho warranty policy

• “Food-grade silicone” is used as though it were a certification. No agency issues one, and no standard is named — a direct contrast with PlanetBox on this same page, which names LFGB. [1] [2]
• “Klean Coat®” is an undisclosed powder coating on the lid. The only substantiation offered is that its ingredients were screened with GreenScreen®; the chemistry is never published. [2]
• Credit, and it is real: the most specific thermal guidance of any lunch box here — oven to 350°F for reheating only, microwave under 1000W, never more than five minutes. Numbers, not adjectives. [1]
• “BPA, BPS, BPF… free” asserted on a steel-and-silicone vessel where those monomers were never plausible. [1]

Sources (3)

1. Klean Kanteen 34 oz Rise Food Box
2. Klean Kanteen FAQ — 18/8 definition, Klean Coat, country of manufacture
3. Klean Kanteen warranty

• “Food-grade… one of the highest quality tiers” is marketing. There is no tiered food-grade silicone scheme, and the claim to be “meeting the EU food safety certification” names no directive or regulation. [2]
• “Must meet certain standards set by the FDA to be legally sold in the United States” is a statement about the law, not about this product’s testing. It is phrased so that a reader hears “FDA approved”, which no food container is. [2]
• No warranty terms are published — only a 30-day return window, on a product sold on durability and reuse. [1] [2]
• Credit: an oven rating of 425°F / 218°C with a stated venting instruction for the microwave. Only Elephant Box also publishes a temperature in this category. [1]

Sources (2)

1. Stasher Reusable Silicone Sandwich Bag
2. Stasher materials and FAQ page

• The lid — the part with the seal, the latches and the food contact at the top — has no published material on either model. A steel-bodied box with an undisclosed lid is not an all-steel box, and the listings do not let you tell. [1] [2]
• “Third-party tested to meet rigorous safety standards” names no standard and no laboratory. It is unfalsifiable in the same way “food grade” is. [1]
• There is no warranty, only a “WeeCare Guarantee — not satisfied? We’ll make it right — every time”, with no duration, no defined coverage and no remedy. [1]
• Country of manufacture is not published. [1] [2]

Sources (2)

1. WeeSprout Large stainless bento with silicone sleeve
2. WeeSprout bento with leak-resistant lid — where 304 is named

• “BPA-Free” on a steel jar is the same empty claim Thermos and Elephant Box make. The lid is the only plausibly BPA-relevant part, and Hydro Flask does not say what it is made of. [1]
• Explicitly not freezer safe — unusual in this category, and worth knowing for anyone who batches and freezes. [1]
• The warranty page could not be read: help.hydroflask.com returned page metadata with no body content. We are recording that as blocked, not as absent — duration, coverage and exclusions are unverified from the maker. [2]
• Country of manufacture is not published on the product page. [1]

Sources (2)

1. Hydro Flask 12 oz Kids Insulated Food Jar
2. Hydro Flask Promise / warranty page — returned metadata only

• No steel grade published anywhere, including in Thermos’s own Care & Use PDF. On a vacuum-insulated jar with an inner steel food surface, that is the single most relevant fact and it is missing. [1] [2]
• On 30 April 2026 the CPSC announced a recall of about 8.2 million Thermos Stainless King food jars and bottles: if perishable food is stored for an extended period, “the stopper can forcefully eject when opened”. 27 reports; three people sustained permanent vision loss. The FUNtainer is not in that recall — but the mechanism is pressure from food left in a sealed insulated jar, which is exactly what the FUNtainer’s own 24-hour limit addresses. [3]
• The care guide instructs you to inspect the gasket, a part whose material is never disclosed. [2]
• Credit: the five-year warranty is one of the longer ones here, and country of manufacture is stated as China. [1] [2]

Sources (3)

1. Thermos 10 oz FUNtainer Food Jar
2. Thermos FUNtainer Care & Use guide (PDF)
3. CPSC — Thermos recalls 8.2 million Stainless King jars and bottles, April 2026

• Credit where due: the user manual names four resins by type — ABS shell, PP tray, ABS latches, TPE overlay. That is more than Yumbox or Simple Modern publish anywhere. You just have to open a PDF to find it. [2]
• Warranty length contradicts itself: the manual says a flat “2 Years”, the warranty page says “1 to 2 years… on most lunch boxes” and points back to the manuals. A buyer reading the warranty page cannot tell which they have. [2] [3]
• The seal is never named. On a box whose entire selling proposition is leak-proofing, the one part in permanent contact at the lid is undocumented. [1] [2] [4]
• Care guidance disagrees with itself: the manual’s feature list says dishwasher, microwave and freezer safe, while the product page and the manual’s own care note say hand-wash the outer shell. The shell is ABS, so the distinction matters. [1] [2]

Sources (4)

1. Bentgo Kids Lunch Box product page
2. Bentgo Kids user manual (PDF) — where the resins are named
3. Bentgo warranty and returns
4. Bentgo FAQs

• The resin is findable only on the spare-parts listing for a replacement container. The main kids’ product page names no material at all, so a shopper must navigate to a spare part to learn what their child’s lunch box is. [1] [2]
• “BPA-free*” carries an asterisk expanding to “in accordance with regulations” — an assertion of regulatory compliance rather than of absence, and a materially weaker claim than the unqualified version most competitors use. [2]
• Care instructions live in a blog post rather than on the product page, and they are stricter than the spare-part page implies: hand-wash the graphic lids, and microwave for a maximum of 3 minutes at 500 W. [3] [4]
• Because of the origin contradiction we are recording country of manufacture as UNVERIFIED rather than repeating either claim. [1] [3]

Sources (4)

1. monbento MB Tresor kids bento product page
2. monbento MB Container MB Tresor spare part — where PP is named
3. monbento Made in France page — which omits MB Tresor
4. monbento maintenance guide — the stricter care instructions

• Silicone seal wear is excluded from the warranty by name. The seal is the part that makes the box leakproof and the first part to fail, so the headline feature is effectively uncovered. [2]
• The “free of” list changes between models on the same site: lead-free is asserted for the Tapas and not for the Original, with no explanation of why. [1] [3]
• Across four Yumbox pages the material language never gets more specific than “BPA-free, phthalate-free”. The steel grade for a different model — 18/8 for the Prêt — is named, so the omission here is a choice. [1] [4]
• Credit: Yumbox publishes an actual dishwasher test specification, “65C/149F, 110 min. cycle”. That is genuinely more informative than “dishwasher safe”, and nobody else does it. [4]

Sources (4)

1. Yumbox Original Leakproof Bento product page
2. Yumbox warranty — the freezer and seal exclusions
3. Yumbox Tapas — where the lead-free claim appears instead
4. Yumbox FAQ — the dishwasher test spec and the 18/8 Prêt reference

• No thermal headroom at all for a children’s product: not microwave safe, not freezer safe, dishwasher capped at 65°C — while other Mepal lines on the same site are microwave-rated to 700W. You cannot reheat in it and you cannot freeze ahead. [1] [4]
• “All products 100% BPA free” is a blanket site-wide banner with no per-product substantiation, no BPS statement and no phthalate statement. [1]
• No warranty is published on the US product pages, the US category page or the FAQ index. [4] [5]
• No USD price is rendered anywhere in the HTML of the US product or category pages. Made in the Netherlands, which is stated plainly. [1] [4]

Sources (5)

1. Mepal Campus bento lunchbox, blue
2. Mepal Campus, licensed variant — same spec
3. Mepal Campus, pink — confirms PP/ABS and 65°C across variants
4. Mepal US lunch boxes category — no prices, no warranty
5. Mepal FAQ index

• The fork, the spoon and the 2oz dressing container are all food-contact items and none has a stated material. [1]
• “BPA-free” says nothing about BPS, BPF, phthalates or the base polymer. It is the narrowest available claim and it is doing all the work here. [1]
• “Reliable, sturdy, and stain-resistant” are the adjectives. None of them is a material. [1]
• No third-party testing or certification cited. No country of manufacture. No warranty. [1]

Sources (1)

1. Walmart — Mainstays Kids 4-Compartment Plastic Bento Box

• CPSC recall 12-089, January 2012: California Innovations recalled about 248,000 insulated lunch box sets because “gel that contains diethylene glycol and ethylene glycol can leak out of damaged freezer gel packs, posing a poisoning hazard if ingested”. One dog died; the recall was later expanded. Different manufacturer — but it establishes freezer-gel chemistry in lunch bags as a real recall category, and PackIt’s is unstated. [3] [4]
• “Nontoxic poly canvas” is a claim without a material. “Nontoxic” is not a regulated term for textiles, and “poly canvas” does not identify the polymer — it could be polyester or polypropylene. [1]
• A five-substance “free of” list sits on top of an unidentified base material, which is the wrong way round. [1]
• A 90-day warranty on a $22.99 product whose failure mode is the gel wall splitting — the part that is both unnamed and the reason to own it. [1]

Sources (4)

1. PackIt Freezable Lunch Box product page
2. PackIt “Our Technology” — gel composition not disclosed
3. CPSC recall 12-089 — California Innovations freezer gel packs, January 2012
4. CPSC — California Innovations expands the gel pack recall

• Microwave-safe for an unnamed resin. A three-minute reheat limit is given without saying what is being heated, and microwave behaviour differs substantially between resins. [1]
• The warranty’s published exclusions are written for drinkware, not for this product: “drinkware that has lost its insulating properties” is irrelevant to an uninsulated plastic bento. It is boilerplate reused across a catalogue, and a buyer cannot tell what is actually covered. [1] [2]
• A lifetime warranty on a $29.99 plastic box is generous on paper; the full policy document was not reachable from the product page. [1] [2]
• Country of manufacture is not published. [1]

Sources (2)

1. Simple Modern Porter Bento Box product page
2. Simple Modern kids lunch collection