Stainless Steel Airtight Container
All-stainless container with a stainless lid and a silicone gasket for an airtight seal - steel food contact, no plastic anywhere.
Plastic-free verdict: Silicone only
Body and lid are stainless steel; the airtight/leak-resistant versions seal with a silicone gasket in the lid. Food touches only steel; the sole non-steel part is the silicone seal. (Plain non-sealing steel tins from Onyx with no gasket are fully plastic-free.)
Verification: Manufacturer confirmed · reviewed 2026-07-05
What it's made of
| Part | Material | Food contact |
|---|---|---|
| container body | Stainless Steel (304 / 18-8) | Yes |
| lid | Stainless Steel (304 / 18-8) | Yes |
| gasket (airtight models) silicone sealing ring on leak-resistant/airtight lids; plain tins omit it | Silicone | Yes |
Straightforward all-steel storage. The food-contact surfaces are stainless steel throughout; on the airtight and leak-resistant models a silicone gasket in the lid provides the seal. A clean choice for anyone who wants steel rather than glass (lighter and unbreakable) and is fine with a silicone gasket - and Onyx's plain lidded tins with no gasket are fully plastic-free.
Pros
- Steel food contact, no plastic; unbreakable and light
- Airtight versions genuinely leak-resistant
- Dishwasher safe
Cons
- Silicone gasket on the airtight models
- Not microwaveable
- You can't see the contents
Categories: Food Storage Containers
Sources
Every material claim above is backed by these. This is the scattered info we centralized.
- manufacturer https://onyxcontainers.com Onyx describes all-stainless containers with stainless lids; airtight models use a silicone gasket
- review https://plasticdetox.org/articles/best-plastic-free-food-storage-containers.html independent roundup listing Onyx stainless containers as a plastic-free/silicone-sealed food storage option