These bearing insert kits are designed exclusively for use with Jims tool ZPN751050 and allow installation of a Timken style bearing and matching spacer on the sprocket shaft side of 2003 thru 2017 Twin Cam engines. The insert has been designed to eliminate the center ring normally used between the bearings. The Jims kit includes a bearing sleeve, mounting hardware, thread-locking fluid, and detailed installation instructions. Stevie's European made bearing sleeve comes only with the mounting hardware.