Fits 300/500/600 Series two-stage snow thrower models, 2005 and after. For Troy-Bilt, MTD, Yard-Man, Yard Machines, Huskee and Bolens units. Easy to install. Replaces O.E. #738-04124, 738-04124A. Includes four shear pins and four clips. 1/4 in x 1-/2 in pin size. Helps protect a snow thrower from damage when the impeller comes in contact with a solid object. MTD Genuine factory parts sheer pins.