Sunnen style MB-770 5″ diameter chuck with reversible jaws. Clamping range .098″-1.574″ Jamming range 1.496″-4.921″. External jaws clamping range 1.496″-4.331″ with chuck key. Custom machined stainless steel mandrel mount test fitted to Sunnen MBB 1660 honing machine spindle.