The construction master pro also includes the ability to custom define your preferences (such as fractional settings), a "paperless" tape that lets you review the previous 20 entries to double-check your totals, and accumulating memory with three additional memory storage locations. It's powered by a two 1.5-volt batteries (LR-44/A76), and the Construction Master Pro has an auto shut-off feature that turns the calculator off after about 8 to 12 minutes of non-use. The 11-digit display measures 2.5 inches by .625 inches.