Digital USB postal scale weighs envelopes and packages up to 10 lb. (4.5 kg) - without a trip to the Post Office or mailroom. Scale connects via USB cable (included) to PC or Mac to use scale with popular online mailing and shipping software - including Endicia InstaRate and DYMO Stamps software. Compact size fits in busiest work space and stores in most desk drawers. LCD screen displays weight in accurate, easy-to-read digital format - in lb./oz. (0 lb 00.0 oz) or kg/g (0 kg 000g). Conveniences include an LED illuminated hold feature, tare function and an automatic shutoff that prolongs battery life. Hold feature locks the weight display for 10 seconds after item is removed from the 8" x 8" weighing platform. This feature is especially useful when a larger package or envelope blocks the display. Tare function weighs items in a container minus the weight of the container. The M10 Digital USB Postal Scale runs on USB power from computer or three AAA batteries (not included).