Designed especially for building and engineer professionals that need speedy access to exact measurements, the Alvin Construction Master V offers calculations like common rafter, stairs, circular key and more. Estimates can be figured quickly, as well, to allow for quick feedback and turnaround while out on the job site. This calculator is packed with features, such as a paperless tape that allows a review of the last 30 calculations, user preferences, cost per unit and much more. The Alvin Construction Master V also works as a standard calculator, too. A hard cover is included to protect it from the inevitable bumps. Also included is a pocket guide that easily attaches to the back of the unit for easy reference. This calculator is covered by a limited warranty that is valid for one full year.