This is a Command System II Adaptive Drawbar Dynamometer that has everything needed to check CAT 40, CAT 50, BT 40 and BT 50 spindles on CNC mills. This is a must have tool for any shop that has CNC mills, or service tech that repairs CNC equipment. There are also a lot of different retention knobs for Okuma, Mazak, Haas, Mori Seiki, and Hardinge. Comes with the fitted case and the operating instruction manual. It operates on two 9 volt batteries that have just been replaced, and this unit works flawlessly. This is in like new condition. This set is $4243.00 new.