When you're mounting an antenna using a ratchet mount, you frequently need an extra five degrees of side-to-side tilt - to get the antenna to sit vertical. These rubber shims gives you that extra capability. Each heavy duty rubber shim adds a half-notch (five degrees) tilt. Stack them at opposing angles for extra height to clear obstructions to the mount. Shakespeare Style 415 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 side/side