Advanced construction math calculator with trigonometric functions for engineering and building professionals. Determine precise angle measurements and solve the most complex design and construction math problems. Built-in functions include stair calculations, common rafters, jack rafter key, circular key, and rake-wall key. Plus, estimate board feet quickly. Features user preferences, exponential notation, backspace to change just-entered values, constant operator, cost per unit, and paperless tape to review the last 20 entries. Operates as a standard math calculator. Includes protective hard cover, pocket reference guide, English and Spanish how-to CD and user guides, long-life batteries, and full one-year limited warranty.