01-29-2023, 03:39 PM
Hi Brian. In looking a little further in that website I gave you I noticed there was a pdf of Cisin's Tube Substitution Guide for 1959. Your tube is located in Group 28. In your photograph I can't tell for sure but it appears spherical with an external tube coating. If that's the case then your tube could be a 21EP4A or 21EP4B. When you check the neck for any markings, also check the broken base... it might have been printed there. Take care and BE HEALTHY! Gary
"Don't pity the dead, pity the living, above all, those living without love."
Professor Albus Dumbledore
Gary - Westland Michigan
