1T4 DF91 Mullard 200 pieces NOS tube valve. You will receive 200 pieces of 1T4 DF91 Mullard NOS. Printed CV785 as per Photo.NOS and supplied in original boxes. All items are NOS and guaranteed unless otherwise stated. Our usual tube tester is the AVO VCM163. One of the best testers in the world. We have been in the tube business since 1981. We have 1,000,000 valves in stock. LARGER QUANTITIES, IF AVAILABLE, CAN BE LISTED ON REQUEST. Our opening hours are Mon - Fri 8am - 4:30pm.