My husband inherited hundreds and hundreds of vacuum tubes. I am in charge of testing, listing and selling. I am at wits end trying to find the answer to my question. Two of the tubes have long pins that plug right into the tester and I get an appropriate reading. Then there are 3 with short pins that don't seem to go far enough into the tester to get a reading. There are no adapters that can be used with the #4 socket. So I don't know how or if I can test these tubes. If this is not the correct forum please direct me to the correct one. I have attached a photo showing the difference between the pins.