The 954 miniature all glass acorn valve is a pentode with a 6.3 Volt heater. Visual inspection shows the three grids within the anode cavity. In 1943 in America the 954 was re-worked onto the B7G base and issued as the 9001.
The normal 5 side pins are supplemented by pins top (a) and bottom (g1) making seven contacts in all.
The small size of these valve enabled them to operate at VHF and up to UHF.
The RCA logo. Looking directly at the grids one can see all three wire grids.
The control grid connection is at the lower left and emerges from the base. The anode connects to the top pin. Below the pin ring is the internal screen. The wording is Made in USA. K1 is the maker's code.
The screen grid is the left pin and the suppressor grid is the right hand pin.
The cathode is the centre pin and the heater is connected to the outer pins.
The envelope is 14 mm in diameter and, including the base pins, is 43 mm tall.
References: Datasheet. Type 954 was first introduced in 1935.