Milwaukee's core bits are ideal for large hole drilling where depth is relatively shallow. The core bit cuts a Kerf only. The usable depth of thick wall core bits is 4-3/8 In. The inside core must be removed by the operator before deeper drilling can be accomplished. The thick wall construction is ideal for larger hammers and more seasoned/cured concrete. A 7-1/2 In. extension is available to allow for the deeper holes to be drilled. The appropriate (Dependant on the diameter) SDS plus drive shank must be used to drive the core bit. Use 48-20-6155 center pin and 48-20-6159 guide plate for positioning and starting the hole. Thin wall core bits are available from 1 In. to 6 In. diameters. See thick wall core bits for cured concrete and/or larger hammers.