Precision Non Rotating Trigger and Hammer Pin and Plate Kit for M&P S&W 15-22 AR's, with Anti Walk Pin and Silver Retainer PlatesPrecision Non Rotating Trigger and Hammer Pin and Plate Kit for M&P S&W 15 22 AR's, with Anti Walk Pin and Silver Retainer Plates. SKU: ATWP02 S Works with M&P S&W 15 22 lowers. The anti rotational feature of our Stainless Steel pins will help lengthen the performance of your AR's lower receiver. By not allowing friction against the inner surfaces of the holes. These, along with the Presma Inc anti walk retainer plates , help with preventing premature