If you have a Model J Senco stapler you may be interested in the kit below.
O-ring Kit for Senco Model J + Bumper
AfterMarket O ring kit and Piston Stop/Bumper to overhaul the Senco model J Stapler.
Includes all the O-rings + Bumper BB0043. Make: Senco Model: J O-ring reference print-out will be included with every order.Available Qty: 12