The 254 is a 100 watt dissipation triode with a mu of 25 and a maximum frequency of 175 MHz for full output. The first example was made by Lewis and Kaufman and is marked LK-254. The second example was also made by Lewis and Kaufman and only marked as a 254. It has a different press and plate seal. Cascade Research as this company was later called, made the third and also marked it as 254. Both of these companys used the Los Gatos "Cat" logo. These tubes were copies of the earlier HK-254 made by Heintz and Kaufman.
Length = 7.13" Diameter = 2.62"
Max voltage = 3000
Max current = 225 ma
Fil voltage = 5
Fil current = 7.5 amps