Description Warranty Information Precise Dovetail Clamp Stem Bore: 5/32 & 1/4" | Clamp Hole: 5/32" Rigid steel construction. Dovetail groove for clamping test indicators. Bores for indicator stem. 5/32" clamp hole. Stem Bore: 5/32 & 1/4" | Clamp Hole: 5/32"