The Variable Stone Thickness Adapter, nicknamed "The S.W.A.T. Jig" is designed to keep the angle consistent when using stones of varying thicknesses. Once the initial angle is chosen with a given stone, the S.W.A.T. Jigs are moved into place so that their index plates rest flat against the stone and then they're locked into position. To change stones, loosen the thumbscrew on the Collar and slide the new stone over until it is flush with the index plate and then lock the Collar into place. Your angle will remain the same regardless of the thickness of the stone.