Simply slide over the drill bit and tighten down at the required depth.
This 7-piece set is supplied in a plastic tube and contains 3, 4, 5, 6, 8, 10 and 12mm collars.
NOTE: Allen keys of sizes 0.7, 0.9, 1.5, 2.0, 2.5 and 3.0 mm are required to fix the adjusting rings.
