Stanley Proto JSCR30 Non-Reversing Compination Spline Wrench 15/16" Black chrome finish is corrosion resistant and visually distinctive. The high contact surface area which is away from fastener points enables turning of highly rounded fasteners. The chrome-vanadium switch lever allows for easy changes in turning direction which helps improve speed. Box end is countersunk for easy application to the fastener. 15 angled offset box end helps keep shank clear of obstructions.