A&D GH Analytical Balances have internal calibration with an internal mass. Automatic Self Calibration automatically calibrates when the balance detects ambient temperature changes. Multiple Weighing Units – g, mg, ct, oz, ozt, dwt, mom, t,TL, counting and percentage modes. Data Memory Function – Up to 200 sets of data stored. Bi-directional RS-232C communication with a PC, printer or other peripheral device. Standard Underhook, ideal for density determination and weighing magnetic substances. Trade Approved models.