CoreMaster 10184 3/8 hex shank Ejecting Holesaw Arbor with 1/4" pilot bit 
CoreMaster is a core-ejecting arbor that holds a standard hole saw to a standard hand drill, and pushes out the drilled core.
 
Features
·         Pops the core out of the holesaw
·         comes with Pilot Drill Bit
·         freestanding clamshell base
·         3/8 in. hex shank
·         1/2 in. - 20 thread
·         Standard pilot drill 1/4" x 3" Long with 1 flat side
·         For Hole Saws 1-1/4"  to 6" diameter