The RE-TI-ASSY-BS2 travel indicator was designed to measure the bump stop travel in big spring applications. With the growing popularity of the "bump stick" this travel indicator will also work with most common brands. The lower plate of the BS2 kit is indexable with the included jam nut. 5/8 x 18 is included. An optional 1/2x20 Jam nut is available (for some shocks and bump sticks).