1779772 snap-back hole saw arbor is made of hardened carbon steel for long life and strength. It is compatible with 20 length-96 length hole saws and drills holes of size 1-1/4 - 6 inch. It features 1/4 inch adjustable pilot drill bit with unique split point design for faster penetration and less walking. It has solid hex shank of size 1/2 inch and thread size of 5/8 inch - 18 TPI. It threads directly into all hole saws and s used for enlarging holes. It drives off pins and prevents threads from stripping.