The 3C24 or VT-204 is a 25 watt general purpose triode with a mu of 25. It is a 25T (25TG) or HK-24 (24G) with a grid pin. Maximum ratings to 60 MHz. The 3C24 was made by Eimac with different base materials as shown in the first 4 examples and by Lewis Electronics in examples 5 and 6. Large numbers were also made by North American Philips (Norelco) as shown in 7, General Electronics (8), H&K (9 & 10) and Cascade Research (11).
Length = 4.38" Diameter = 1.44"
Max voltage = 2000 VDC
Max current = 75 ma
Fil voltage = 6.3 volts
Fil current = 3 amps