3/8" Dr. Extensions, 3/8 in (female square); 3/8 in (male square) drive, 3 in

Designed for superior performance in a variety of lengths for hard-to-reach applications. Forged and machined for best fit and unyielding strength. Precision heat-treated and tempered for optimal hardness, ductility and durability. Easy to read stamp pattern in order to quickly determine opening size. Meets and exceeds ASME B107 hand tool standards.