The compact, accurate DYMO® M5 Digital USB Postal Scale weighs envelopes and packages up to 5 kg (11 lb). This scale is packed with great features - including a “hold” feature that locks the weight display for 10 seconds when the screen is obscured by a larger item, a tare function for accurately weighing items in a container, and an automatic shut-off that prolongs battery life. Free DYMO® Scale Software. Display the scale weight on your Mac® or PC screen. Download the DYMO® Scale software: www.DYMO®.com/scalesoftware. Powered by 3 AAA batteries (not included) or USB cable (included) connected to PC or Mac® (Works with Windows® XP, Windows Vista™, Windows® 7 or Mac OS® v10.4 or later).