The Starrett DB2 is a debris collector for hole saws. It is designed to prevent debris clean-up and to protect the drill itself. DB2 prevents dust from entering the motor of the drill. It also means that you do not have to wear a mask when drilling. DB2 can be used with hole saws up to 121 mm (4 3/4 inch).
Simply place the shank of the arbor through the hole on the DB2 and attach the arbor to the drill as normal. You can pull the DB2 down to view the work area better. The DB2 debris collector flexes as you drill the hole. Once the hole has been drilled, all the dirt and debris is collected inside the DB2 for you to dispose of nice and easily.