Extremely Rare Round Type - N Valve ,1913 Start Price GBP 600.00 Current Price GBP 600.00 Time Left - Bid Count 0 Buy It Now Price GBP 800.00 Reserve Price - Start Time Sunday, August 17, 2008 End Time Sunday, August 24, 2008 Location Auckland, Auckland See more about 'Extremely Rare Round Type - N Valve ,1913' Description Extremely Rare Round Typ -N Valve,  First British Triode developed by Capt. H.J. Round for Marconi in 1913 .  An Essential Valve for any Serious Valve Collection !. Filament is open, as most of them are.Socket is not included. Tube is marked Marconi's W.T.Co. Type 2V-PIF , No. N7789 . Private Sale ,No Guarantee, No Returns. Airmail 8 Pounds. Place a Bid!