Tapmatic 30X head on 1/2" shank; comes with the 1/4" flex collet (8 ribs, good condition), and two wrenches (not original- I made them quickly once when I couldn't find the originals). Just tested with a 1/4-20 tap, works as it should. The impact marks on the stop bar were there when I got it years ago; probably run at too slow a speed with a dull tap.