If you can push sideways on your trigger and feel play, your wiper button may loose contact with your wiper board and cause erratic operation. Ball bearings will cut this play to zero and reduce trigger effort and improve your controller's mechanical reliability.
The Difalco DD721 Ball Bearing Upgrade Kit includes the DD719 Trigger Pin, 1/8" ball bearings and the special shim, spacers, and Nyloc nut to correctly install the ball bearings. This upgrade kit is for all brand controllers (even stock Parma resistor controllers) and our modules to upgrade to a ball bearing trigger that are not already using our DD719 Trigger Pin. For Parma or Kelly triggers. If you have a brand controller that is not a Difalco, you will need this kit.