Both tubes tested well for Gm, shorts and gas with the Heath TT-1. See photos for Gm results. Rp is 1300, new is 2000 Mhos.
Pair RCA Type 53 Tubes, Twin Triode, ST Shape, Tested
$24.0
Brand
RCA
Type
53
Model
53
Country/Region of Manufacture
United States
Unit Quantity
2 Tubes
condition
Used
A nice pair of 40s #53 tubes by RCA.