When you're mounting an antenna using a ratchet mount, you frequently need an extra five degrees of tilt one way or another - front to back, or side-to-side - to get the antenna to sit vertical. This kit of four rubber shims gives you that extra capability. Each heavy duty shim adds a half-notch (five degrees) tilt. Stack them for extra height or for compound angles. Shakespeare Style 416 Shim Kit for Ratchet Mounts Heavy duty rubber Each shim adds a half-notch (five degrees) tilt Stackable for compound angles Stack at opposing angles to add height (for clearing obstacles on mounting surface) 24 shims per kit, all front/back