Protects Your Snowblower - Purposely designed to snap if the auger jams or clogs - Manufactured to rupture at the designed load limits - 5/16" Diameter Fits Ariens Professional two-stage snow blowers - Single bolt is Ariens part number 51001500 - Check your Owner's Manual for the correct part number 3-Pack - Replace both existing shear bolts if necessary - One spare, just in case