For mounting AGD indicators with 3/8" (9.5 mm) stems in gaging and work location fixtures, these collets simplify fixture mounting. Screw the collet into the fixture or into our 648 Depth Gage Base, insert the indicator into the collet and tighten it in place with the hexagonal nut. Internal collet fingers grip the stem with equal pressure to eliminate spindle binding. Made of steel with black finish. Overall length of collet and threads is 1". Split Collet, English Thread, 1/2-20NF Overall length of collet and threads is 1".