When you have a fixing that is out of reach this tool really is invaluable to drill, screwdrive or countersink. Overhead, in the back of a cabinet or under a floor. Retractable and with a total reach of 600mm there are also 5 other locking stages of length 360, 410, 460 and 510mm. 1/4" hex fits into your chuck whilst the 1/4" hex chuck has a bit lock. The body of the tool does not spin so you can hold and guide whilst driving which is important due to the distance you may be working. Well made this is a gem of a tool when some things are just out of reach.