The Corona Clipper razor tooth 13-Inch replacement tree pruner saw blade for Corona models TP 6870, TP 6850, TP 6830, TP 6780, TP 6570 and AC9000 The razor tooth design cuts twice as fast as conventional saw blades as it cuts on the pull and push strokes. The blades are cut on three sides for quick cutting through limbs, branches and other landscape items.