This scale features both internal calibration and self-calibration. The unit has an internal calibration weight, one-button calibration system and recalibrates whenever it detects temperature changes. The scales come with standard WinCT software (Windows Communication Tools Software) which provides easy transition of weighing data from the balance to PC or laptop (with RS232 USB cable). The display is on a swing arm, which can go up to 25" high. Weighing modes: g, kg, ct, dwt, piece counting and percentage mode. Unit: 14¾" x 24" x 5".