The 852 that was originally designated UX-852 by RCA is a 100 watt dissipation triode with a mu of 12 and full ratings to 30 MHz. First available in 1927. It was one of the first tubes used into the VHF range. Sylvania produced these tubes with carbon anodes as shown in the second and third examples with metal and ceramic bases. The fourth example was marked as National, but appears to be a re-build of an RCA tube. The De Forest version of this tube was the 552.
Length = 8.81" Diameter = 4.59"
Max voltage = 3000 (orig 2000)
Max current = 85 ma (orig 75 ma)
Fil voltage = 10
Fil current = 3.25 amps