Commonly referred to as a ldquo4th hand rdquo the park tool cable stretcher pulls cables tight for adjustment of derailleurs and brakes it features one hand operation with a thumb lock to hold the cable tight while your hand is freed up to tighten bolts and nuts a must have for any shop home or professional park tool cable stretcher features also known as a fourth hand this tool speeds up work on brake and gear cables one hand operation to tighten cables with a thumb