The cutter protection strip is one of the most important parts on the cutter. It allows for straight and true cuts without any jagged edges or ruined material. The teflon strip is the black strip under the blade that runs the length of the cutter. Worn teflon strips cause inconsistent cutting; uncleans cuts, and premature blade wear. For the best cutting results, replace the teflon strip every six months and it is always a good idea to have one as a back-up. Compatible with the Q-Series Q160, Q64, Graphtec FC7000/FC8000/8600-160 cutters.