APPLICATION: Fits for 1989-Current Cummins 3.9L 5.9L 6.7L. Will fit Paccar PX-6, 1989-2016 Cummins 4BT 3.9L, B Series 5.9L, ISB 5.9L 6.7L and QSB 5.9L 6.7L. FUNCTION: This kit is designed to installs seal numbers 3937111, 3904353 and the seal & wear sleeve kit 3802820. BENEFITS: Made to properly place the crankshaft seal without leaks. Help to properly press the wear seal into place evenly. ( NOTE: Installing the seal uneven can cause leaks prematurely, make sure the job is done right with this installation tool.) ALTERNATIVE TO: .