Urethane O-ring for Tube Cap on most older CO2 guns, including Benjamin 250, 252, 257, 2600, 350, 353, 357, 360, 363, 367,3600, 360, 363, 367, 422, 3600, Crosman 150, 157, 1100, 160, 166, 167, 180, 187, 400. 600, 677,700, 707. Daisy 780, 790, Smith and Wesson 78G, 79G, and others. The urethane O-rings were not available when thses guns were made, so Crosman could not specify them. We recommend the old style CRS150-054 for use on the compression chamber or valve body where it is not subjected to movement.
