Same type of rubber as the originals.

Piston O-rings

Item ITEM# Price Quantity O-ring P-2/10 See details 30002 $1.00 O-ring P-20 See details 30020 $1.00 O-ring P-100 See details 30100 $1.00 O-ring P-200 See details 30200 $1.00 O-ring P-1000 See details 31000 $1.00 O-ring P-5000 See details 35000 $1.00  Add Selected