Introducing another unique JIMS® tool by master tuner and multiple land speed world record holder Hiro Koiso! Designed to test ring gaps with a unique proprietary cutout feature, the flanged shape allows the piston ring to fit squarely into the cylinder bore every time. Simply install the tool into a cylinder bore and place your piston ring onto the tool. You can view the ring end gap in the “Key Slot” and use JIMS® Feeler Gauge Tool No.908 to determine your exact end gap measurement. JIMS® Twin Cam Piston Ring End Gap Tool works for 95”, 103” and 110” H-D engines with 3.875” or 4.000” bore and 120”, 131”, and 135” JIMS engines with 4.125” or 4.310” bore. Made in the U.S.A. and backed by a lifetime warranty, please visit us at www.jimsusa.com, find us on Facebook or call 805-482-6913 for more!