These roofing ASB Utility Blades are 75% stronger than Stanley's 11-983 Hook Blade resulting in fewer blade changes. The edge is engineered to withstand the rigors of cutting today's heavier and thicker roofing materials. Cuts roofing shingles, felt paper, Tyvek, foam board, insulation, shingles and other building materials. Designed for use in fixed blade knives only. ROOF callout is laser etched on blade to prevent accidental mixing with standard blades.