CONSISTENT LEVELING FOR LONG RANGE ACCURACY Excalibur&';s Anti-Cant Insight Scope Level will help maintain your crossbow&';s horizontal axis while keeping the arrow on its vertical plane. Its lightweight, unique design can quickly and easily be installed on your scope giving periperal visibility when looking through the scope. Fits all scopes with diameters from 1.495" -1.635" (38mm-41.5mm). Product # 73699