Calculated Industries 4065 Construction Master Pro Advanced Construction Math Feet-inch-Fraction Calculator for Contractors, Estimators, Builders, Framers, Remodelers, Renovators and Carpenters ROOF, RAFTER, FRAMING KEYS  give you quick solutions for common, regular, irregular jack and hip/valley rafters, roof surface area, cutting angles COMPLETE STAIR LAYOUT FUNCTIONS  let you quickly solve for number of treads, tread width, risers, stringers, stairwell openings, inclination angle QUICKLY ESTIMATE MATERIAL COST  for all your layouts and construction projects, square footage, studs on center, drywall, roofing, blocks, footings RUGGED AND CONVENIENT  set preferences that you want for fractions, riser and floor height, studs on center and it comes with an Armadillo Gear case CONVERSIONS ARE A SNAP  work in the units and format you want without having to struggle with math  feet and inches, fraction, decimal or metric