ITW Ramset 00022 HammerShot Low Velocity Powder Actuated Tool Replaces HD22 Light weight duty tool designed for applications such as small room additions and basement remodels The model HD22 is a low velocity piston type fastening tool Designed for use with Ramset 0.22 caliber CW powder loads and Ramset fasteners HD22 single shot .22 caliber powder actuated fastener tool Delivers a powerful single shot to fasten your projects