The first choice everywhere a ring wrench cannot reach. Therefore, it is ideal for tightening screws on brake lines, tie rods, exhaust temperature sensors, diesel fuel lines, or air conditioning pressure sensors. It can be attached laterally to nuts or screws like an open-end wrench. The jointed arms with a closing spring and integrated opening aid provide a self-locking effect and power transfer to the flanks of the screw head. The ratchet effect allows for quick re-engagement. Additionally, the marking of the operating direction on the wrench head ensures easy handling.