These are the two main o rings for the Ce Chem Limited sprayable seam sealer gun.

• The smaller O ring is for the seal between the cartridge end and the gun body. 
• The larger O ring is the seal between the threaded, removable cartridge chamber and the main gun body.

These are made from hard wearing, yet very supple Nitrile Rubber and are a replacement for the original seals.

Please note that cleaning the gun with a strong solvent such as thinners, will damage the seals.