Superior Electric J3113HH 1/2" Capacity Keyed 5/8"-16 UNF Drill Chuck Replaces Milwaukee 48-66-1381/48-66-1380 (Drill Chuck) & 48-66-3280 (Chuck Key) Maximum capacity(in): 1/2" Runout(in): 0.007" Minimum Capacity(in): 0.08" Sleeve Diameter (in): 1.8" Mount: 5/8