MARINE GRADE STAINLESS STEEL - Marine grade stainless steel impact socket features with added strength, higher working temperatures and corrosion resistance. It’s much stronger to stand greater impact force than chrome vanadium ones. COLD FORGING & HEAT TREATMENT - Cold forging and heat treatment greatly improve the performance of the socket with enhanced hardness, increased wear-resistance and lifespan. EXTRA DEPTH - Provide more space to accommodate longer bolts and wider applications to facilitate your work. UNIQUE DESIGN - The lifespan of both the fastener and socket will be greatly prolonged with the force distributed to the inwall. WIDELY USED - A fine and dense coating brings more corrosion and wear resistance for longtime use. Compatible with all 1-5/8", 2-7/16", and 3-1/4" channels and Strut. For use with All 1-5/8", 2-7/16" & 3-1/4" Tall channels and Strut 2