For routing, grooving and joint cleaning of deteriorated mortar between brick, cement block, concrete pavers and flagstone joints. Grind out a vertical or butt joint in seconds without damage to the existing bricks or block. Eliminates saw overcuts.A faster, more efficient way of removing deteriorated mortar in brick joints, cement, cinder blocks, pavers and stone joints in walkways, patios, stone curbing. May be used either wet or dry with power hand tools, i.e. angle grinders, small power hand saws, routers and electric drills.