MuscleChuck Camless Quick Change 1/2-Inch Chuck Fits DeWALT 615,616, 618, 621 Type 3:Fits DeWALT 616, 618, 621 1/2-inch shank can use bushings for 1/4-inch, 8mm and 3/8-inch shanks. Length: 1.3 in (Approx) Run Out: &lt;.002 in High Quality Alloy Steel. All materials and processes certified to aircraft standards.