The Beta Tools Self-Locking Wrench, No. 186, is designed to automatically lock around the head of a fastener. The wrench has two working ends: one accommodates fasteners from 8mm to 17mm, and the larger end accommodates fasteners from 14mm to 32mm. The design of the teeth allows it to remove damaged fasteners as well as hexagon, spline square head an Torx fasteners, according to the company.