OLFA 18mm Heavy-Duty Hook Snap-Off Blades are ideal for cutting materials like flooring or roofing. The unique hook shape protects the material underneath the cut. Made from high quality carbon tool steel. With four segments per blade, a fresh sharp edge is always available quick and easy. For use with OLFA Models: L-1, L-2, L-5, LA-X, NL-AL, and NOL-1. Use these blades for roofing, linoleum, shrink-wrap, rope and twine, and more.