The JOMAR Professional Degree Wheels are available in both 10" and 14" diameter with a 1.250" center mounting hole, designed to use the JOMAR mounting hub and adapter kits (sold separately). The hub bolts to the crankshaft using the proper adapter, and features a knurled nut that allows quick and secure adjustment of the degree wheel . The wheel is degreed on both sides; side A for checking lobe centers, and side B for checking cam duration. Instructions and laminated reusable spec. Sheet are included.