MIT 3/8 -DRIVE X 6 EXTENSION BAR features: Drop Forged Chrome Vanadium Steel, Heat Treated and Triple Chrome Plated for Extra Durability, Tapered 6-Point or 12-Point Socket Ends for Easy Access to Nuts and Bolts, Featuring the Opti-drive System A Revolutionary Design That Allows You to: Apply Greater Torque without Damaging the Fastener or Socket, Distribute Stress Evenly on the Socket to Prolong its Life, Reduce Wear and Tear on Socket by Optimizing Flat Surface Contact, Eliminate Corner Contact, so Fasteners do not Round off.