The VT-177 is a dry battery diode triode for receiver use. The 1H5GT is the same valve but on an IO base. In a TRF receiver the diode would provide AM signal demodulation and the high μ triode would be the first audio voltage amplifier.
The code SC95A.
The dome has etched into it the commercial Type code of 1LH4.
The Sylvania name and the USA Government procurement code of VT-177. Inside is obscured by the gettering but here the lower mica can be seen.
The wide glass tube envelope is 29 mm in diameter, and excluding the B8B base pins is 53 mm tall.
References: Data-sheet, 1040 & 1043. Type VT-177 was first introduced in 1940. See also1940 adverts.
