ACCUTECK All-in-1 Series W-8250-50bs A-Pt 50 Digital With Ac Adapter, Silver Fold up mailer holder--stand upright to 90 degrees for rolling tubes and irregular packages Capacity--up to 50lbs, sensitivity--0.1oz0-25lb), 0.2oz(25-50lb), reading modes--pounds/ounces, ounces, kilograms/grams, grams Key functions--tare(allow you to reset the display to 0.0), hold (especially for weighing a over-sized item) Self-calibration technology--does not require a 50lbs weight, you can choose any known weight starting from 5 lbs. for calibration purpose Power-- run on 3 x AAA batteries or 5v adapter (both included)