Features: Made of fine quality chrome molybdenum steel, wear-resistant, not easy to rust. Grips and removes damaged, rounded-off and rusty nuts and bolts with ease. Maintains even an equal force on all sides of fastener opposing rounded corners. It easily handles high torques, firm and properly gripping any nuts and bolts within its continuously adjustable size range. One-handed operation, fits any standard 3/8 drive wrench. Handles much higher loads than other adjustable tools. Replaces over 30 sockets from 3/8 to 3/4 and 10 to 19mm.