The 6350 is a premium quality medium μ double triode. The design is similar to the 12AU7 but the 6350 has been designed for computer circuits and other control applications where the valve can be in the cut-off condition for extended periods.
The data-sheet gives operating conditions for Class A amplifier service and these are listed below.
The RCA logo.
One anode face view.
The thin glass tube envelope is 21 mm in diameter, and excluding the B9A base pins is 61 mm tall.
Reference: Data-sheet. Type 6350 was first introduced in 1957.