Umarex Capsule/Bulb Seal. (Manufacturer Part Number: 416.60.10.1) for  Umarex Umarex CP99 and CP Sport Pellet CO2 Pistol. The Co2 Bulb Seal/ Washer inserts into the butt for the Co2 Pistol. Not suitable for the BB firing CP99 Compact

13mm Outer Diamater
3.8mm Internal Diamater
3.5mm Thickness