With the Dymo USB Digital Postal Scale (5 lb) you just put your mailing item on the scale, wait a few seconds and press the weight button. The correct mailing weight is displayed on the unit's easy-to-read LCD. With Dymo Stamps software (NOT included) installed on your computer, the precise cost of postage is calculated and is ready to print from compatible Dymo LabelWriter printers. The scale has a capacity of 5 lb and it can weigh in ounces and grams. Its auto-off function shuts down the power after two minutes of inactivity (when battery operated). The scale operates on USB (2.0) or a 9-volt alkaline battery (not included) and is PC and Mac compatible.