Dalcini Stainless
Dalcini is a plastic-free brand in the strict sense: its containers are 100% food-grade 304/316 stainless steel, seamless (no chemical adhesives to join seams), and finished by hand-buffing rather than any coating. No BPA, PVC, phthalates, lead, or aluminum. The community names it alongside ECOlunchbox and LunchBots for people who want steel bento with no plastic parts; the trade-off, as with all gasket-free steel, is that the plainest boxes aren't fully leak-proof.
How clear are their specs?
States 304/316 food-grade stainless, seamless construction with no adhesives, hand-buffed with no chemical coating, and a detailed free-of list - materials fully disclosed.