3-jaw caliper inside design, lock pin handle pull into end, then easy to lock
the drawbar (if pin did not pull to end of bottom it might can not take out drawbar,
in case it happened just use the Rubber Hammer to knock the end of handle, then it can release again.
attached with pulling handle and plastic box
dia. 110mm x 36mm (exclude the position block)
it can suit for CNC Milling & Lathe