Unique tooth design allows the blade to cut on both the up and down stroke. Cuts a little slower for more control, which is especially useful in delicate fretwork. Finish is smooth with clean, sharp, splinter-free edges in hard/soft wood, plywood, plastic and Corian. Two-way cutting action prevents melting behind the cut in most plastic including acrylic, Lexan (polycarbonate), fiberglass and Plexiglas. Has no top or bottom for easy blade installation. Blade can be turned over for a fresh new set of teeth.