Leather piston cup seal 1.1 inch diameter. Some fitting might be required. Use for Crosman 3100, Anschutz 335, Luczink 87, etc. This is a standard Leather cup seal. Leather naturally varies in thickness, however, these seals are made to very close tolerances. They will expend a little to fit an out of round or oversized compression tube or can be reduced in diameter with sand paper and made to fit a slightly undersized compression cylinder. You might need to purchase LEA1.1A to accompany this seal.