double-ended-triode

This tube is a double ended type with a tubular bulb and a nickel plated B4 base at each end. It is approximately six inches long. Development of this tube is attributed to Josip Sliskovic in the book " "Historic Vacuum Tubes for Telephony and Radio" by Franz Pichler. Slipkovic worked for many years with Kapsch from 1927. A date for design or manufacturer is unknown but it may be a development of his before his interests at Kapsch started.