Anshun Tiger Grip® are invented to remove stubborn hex fasteners. Patented Anti-Slip design is perfect to remove or tighten up to 85% corner worn hex head. Yes, bi-directional anti-slip makes Anshun Tiger Grip® better than all other ant-slip sockets in the market. While working on non-worn hex fasteners, the flank design makes sure Anshun Tiger Grip® does not bite on the surface and leaves no markings. 16 metric sizes available for users to work on corner worn nuts and bolts without getting hurt ever again. A robust PE-HD BMC is included for easy storage and transport.