Stanley Proto's hex key line features a variety of sets to suit nearly any user. Keys include a standard six-point hex, round-head, Torx, and spline-head styles. All are made to precise tolerances for a tight fit, and are available in fractional and metric sizes, and in standard reach, long reach and extra-long reach lengths. The longer lengths offer superior leverage, high torque and in-line access. Proto keys are made from heat-treated, tempered alloy steel that resists wear and rotational distortion, making them last longer.