MYKROLIS TYLAN 2920 SERIES FC-2921V-J MASS FLOW CONTROLLER. Used: An item that has been used previously. The item may have some signs of cosmetic wear, but is fully operational and functions as intended. This item may be a floor model or store return that has been used. Any accessories, manuals, cable and etc that are not in the picture listing or mention, it is NOT INCLUDED. For item condition not as described, defective.