SAPSONS Stud Tighteners also known as Stud Drivers is used for speedier tightening of threaded studs with the help of an impact wrench. This is ideal for use in the assembly and maintenance of engines. The range covers stud diameters M5 to M36 (metric) & 14" (6.35mm) to 1.12" (38.1) UNFBSF (SAEBRITISH) in 38" to 1" square drives. The tool has a cross hole and groove for locking pin and ring arrangement. Stud Tighteners to suit BSW, BSF, UNC OR UNF Threaded studs also available on request as specials. Extra Deep Stud tighteners also available on request.