Faithfull Electrical Back Box Cutters are a labour and time saving system, designed to cut sockets in blockwork and brick walls for the siting of electrical back boxes. They are used in conjunction with lightweight 2kg SDS fixing hammers with a rotation stop function. This TCT cutter bit is designed for use with Faithfull box cutters to form recesses for either single or double electrical back boxes. It cuts 77mm round holes in block, soft brick and concrete. The cutter has precision machined cutting edges and is designed for use with 2kg SDS Plus rotary hammer drills. Cutter Bit Size: 77mm Set includes:1 x SDS Plus shank drill 8 x 160mm.1 x SDS Plus flat chisel 20 x 140mm. Use in conjunction with FAISDSBOXSML and FAISDSBOXLRG box cutters to form recesses for electrical back boxes.Additional Information:• Shape: Circular