PDPAWL Drive Pins with 1" Washer - Includes pre-installed 1" washer. For structural steel and extra hard concrete: for A36 and A572 grade 50 structural steel (red strip loading recommended). 0.157 inch diameter for higher compressive strength. Manufactured to tight tolerances for superior performance. For Simpson Strong-Tie Powder Actuated Tools - PTP-27L, PTP-27S, PT-27, PT-22P, PT-22, PT-22GS, PT-22H. Also compatible with 721, D-60, U-2000, System1, System 3 and other low speed tools.