00.10.00648 556 is the replacement cutting head for Dahle Professional Series 556 & 558 Rolling Trimmers. Designed for safety and accuracy, the ground steel cutting blades are encased in a plastic housing that virtually eliminates the chance of personal injury. The rotary action of these trimmers allow the blade to cut in either direction and sharpen itself as it cuts. It's this self sharpening action that produces a clean burr-free cut and guarantees many years of smooth precise cutting. Dahle's Premium Rolling Trimmers are designed for heavy duty applications where precision is essential.