AJC Knives are designed with the professional in mind. See Our Blades for Roofers. Click.. . AJ-057MCGA Guardian Angle Knife Specifically designed for cutting shingles. Features hand and knuckle protection. Designed to reduce fatigue and increase leverage. Comes with AJC's big hook, bowtie, and utility blade. JUST $10.95 AJ-0574208 Angle Knife Angled to keep hand away from work. End cap screws off for fast, tool free blade replacement. Extra blades store inside handle. JUST 6.95 AJ-057RK3Y Roofers Knife Stamped two section design provides blade storage. Wing nut allows for tool free blade replacement. 3 AJC bowtie blades are included. JUST $4.95