The Blade Stop on your shear is a replaceable wear part which has two functional edges. Blade Stops wear out after extended use, leaving backing materials, fibers, or small chips uncut or frayed and reducing cut quality. Once one edge is worn, flip the Blade Stop over to use the other side. To flip (or replace): Remove the aluminum anvil from your shear by unscrewing the anvil screws with a 4mm (7/32") hex wrench or #3 Phillips Screwdriver (depending on the model), then remove the plastic blade stop strip. Reinstall with a new Blade Stop edge facing upward.