Ever tried drilling a pilot hole for a screw by eye in a hinge countersunk hole? 95% are sure to be off-centre with the screws ending up crooked. For perfectly aligned hinge screw pilot holes the conical nose of the bit sits in the hinges countersunk hole making virtually impossible the drill anywhere other than in the exact centre. When pushed the spring-loaded nose retracts allowing the actual drill bit to bore the pilot hole. The drill bits are high speed steel for longevity and quality results. The nose piece features three slots ensuring there is sufficient clearance to prevent clogging in use. Each bit is clearly marked with its size for identification. The universal 1/4" hex shank is compatible with all quick change systems drill/drive systems.