Factory direct seal silicone rubber o ring for thermos

A rubber O ring for thermos lids provides a replaceable circular seal within the closure. The custom diameter and section should match the lid's receiving seat and the vessel contact surface. A correct replacement restores the intended geometry without requiring excessive tightening of the lid.

Check the ring recess and the mating rim for residue or damage before fitting. A ring that is too thick can prevent the closure from reaching its intended position, while an undersized section may leave insufficient contact. The selected silicone compound should suit the contents, temperature, and cleaning routine of the thermos.

Place the ring evenly without twist and inspect it after opening and closing the lid. Keep the recess beneath it clean using the thermos's intended care method. The complete closure determines the permitted storage and handling conditions, so a new ring should not be assumed to make every orientation leak-free. Replace torn or permanently flattened rubber with the matching section, and address damaged seating surfaces rather than relying on additional compression to recover the seal.

Material options

Silicone. Custom formulation and color for the intended contact conditions.

Hardness selection

Silicone: 20–80 Shore A. A ring that is too thick can prevent the closure from reaching its intended position, while an undersized section may leave insufficient contact.

Custom dimensions

The custom diameter and section should match the lid's receiving seat and the vessel contact surface.

Fit & assembly

The complete closure determines the permitted storage and handling conditions, so a new ring should not be assumed to make every orientation leak-free.

Use & inspection

Replace torn or permanently flattened rubber with the matching section, and address damaged seating surfaces rather than relying on additional compression to recover the seal.

Photos illustrate structure or material only. The custom diameter and section should match the lid's receiving seat and the vessel contact surface. ETOL directly manufactures custom-shaped silicone and rubber parts to your requirements.