ACCURACY AND DURABILITY: This aluminum rafter angle square boasts a solid aluminum body with CNC machined edges for greater accuracy and durability. BUILDERS AND CONTRACTORS: The thick edge works as a saw guide. Use it directly with the saw for cross or angled cuts via the etched protractor scale, or indirectly with scribing notches to mark rip cut lines. SIMPLIFY STAIR LAYOUT: The integrated distance and angle scales let you quickly and accurately mark your cut lines on your stringers and has scales for cutting hip, valley and jack rafters. ONE NUMBER LAYOUT: For roofs, solar panel supports, stairs, cabinets, trim work, and many other layout projects. ADDITIONAL FEATURES: Permanent graduations with easy-to-read numbers, continuous scribing notches for 3-1/2" and 5-1/2" boards, 2x4 dimension markers, low-glare powder coated finish, scribe notches 1"–5-1/2" in 1/4" increments.