new TT21 tubes , tested and guaranteed. These work the same as KT88 and 6550 tubes, EXCEPT they have different base connections, use an anode cap, and have an anode (plate) voltage rating of 1,250 volts. Full original data on TT21: http://frank.pocnet.net/sheets/126/t/TT21.pdf
Note regarding specs: Use at CCS or lower ratings for longest and most reliable service. All normal audio amplifiers should adhere to CCS limits. ICAS limits are meant for short term use in amateur radio transmitters.
Price is per tube. Offers on this item considered for quantity.
This item is shipped from Britain, in North America or Asia please allow 2 to 3 weeks for delivery.