The 100TH or VT-218 is the new designations for the 100T "HI" version made by Eimac. It is rated at 100 watts with full power to 40 MHz and had a mu of 38. The 100TL was the same tube with a mu of 14. The first example is an early example of the Eimac tube with the bent grid support wire and the second shows the shorter wire version. Post war tubes had their construction materials changed. The fifth example was made by General Electronics, the sixth by GE, the seventh by Jennings, the eighth by ICE, the ninth by Lewis and Kaufman, the tenth by EEI, the eleventh with the black base by Industro, the twelfth by H&K and the thirteenth by Sylvania. The foutreenth example is marked as an Arctarus tube but is obviously an Eimac tube that has been re-branded. The glass work around the grid seal is very poor and could have been a reject. The Japanese designation for this tube is the 4T17.
Length = 7.75" Diameter = 3.19"
Max voltage = 3000
Max current = 225 ma
Fil voltage = 5
Fil current = 6.3 amps