08-21-2009, 06:04 PM
Yep, they are out there. I'm thinking they were the tube of choice for the 1936 series RCAs like 9K3, etc. Of course a straight type tube can be used to replace them in those radios because of the way the mounting bracket was made but the opposite is not true in many sets where only a straight sided tube can be used.
-Bill
-Bill