The 6BC5 is a sharp cut-off pentode designed for use as an IF amplifier in American television receivers.There are three variants differing only in heater parameters. the 3BC5 and 4BC5 have controlled heater warm-up times for use with series heater chains.
The lower mica is two layers and so this may be suitable for use in areas of vibration.
The central band obscures the internal details.
Made in USA.
The thin glass tube envelope is 18 mm in diameter and, excluding the B7G base pins, is 46 mm tall.
Reference: Data-sheet. Type 6BC5 was first introduced in 1949. See also1949 adverts.