Type 8012 is a VHF/UHF transmitting triode and dates from the early 1940s and has a thoriated tungsten filament as did the earlier 1628.
The control grid can pass up to 14 mA grid current and dissipate 1.6 W. The maximum frequency of operation is in the region of 500 MHz. The 8012A is rated at full power at 500 MHz.
The side pins extend to 60 mm. The anode is connected to the set furthest from the cathode by flat sheets. The grid is connected to the set of pins on the right. The three base wires connect to the heater and cathode. The lettering is etched into the glass. The getter holder plate can be seen on the left and unlike 8012 almost no discolouration of the glass exists.
Here is another example. The pins are corroded but the wires indicate that this valve has never been used.
The RCA logo and Type designation at the top. The grey anode with tape connecting to the side pins also shows the fact that the pins are multi part to ensure the correct coefficient of expansion as the metal passes through the glass.
The anode is made in four sections that are stitched together to form four heat radiating flanges.
The thin glass tube envelope is 25 mm in diameter and, excluding the base wires, is 93 mm tall.
References: Datasheet & 3002. Type 8012 was first introduced in 1942.