The adapter with the guide drill is used to install crowns with a diameter of 19 to 29 mm, with the landing 3/8 ". The crown is screwed onto a threaded connection, and the holder is securely fixed in the tool chuck hex shank. You can quickly replace the crown, without additional tools. It is convenient and saves time. Landing thread and shank as not to lick Holder is made of durable tool steel. Due to the hexagonal shank holder does not slip in the chuck. Add to basket holder and securely fix his crown drills. Properties securely fixing the crown (tsifenbora) threaded connection; You get a smooth hole through the drill guide; Quick change tsifenbora without extra tools; Hexagonal shank for drills and drill presses.