The 270A or WE270A is a 500 watt triode with a mu of 8.8 originally made by Western Electric. The first example was made by Amperex with a graphite anode and a composite plate insulator. The second example is probably a Western Electric with a metal anode and ceramic anode insulator that was rebuilt by California Tube laboratory and was used by radio station WKZO in Kalamazoo, Michigan.
Length = 17.00" Diameter = 4.00"
Max voltage = 3000
Max current = 175 ma
Fil voltage = 10
Fil current = 9.75 amps