Its reduced

54 cm height mounted

Inside there are three moveable

Unfortunately this has been copied several times to decreasing quality

bimetallic crown professional drill bit FINISH:BIMETALLIC CROWN PROFESSIONAL DRILL BIT Its reducedThe primary application for our round ceramic wall and ceiling sockets. This will drill the correct hole size for the installation of the back box for Katy Paty. Bimetallic crown a professional tool for drilling holes. For boxes in hollow walls. Supplied with clamping and centring drill in the length of 70 mm. Clamping 11 mm hexagon. Use this drill bit on the following materials and walling = alloyed and non alloyed steels with strength up to 700N m2,