The U920 is an output triode. The trade name on the envelope is Ostar. Also on the glass are the heater rating. Ostar Ganz made a range of valves with a mains heater. The base pins are of simple split construction.
The Ostar brand name, heater rating and below is the Type designation. The 920 can just be seen in the image. In the UK with nominal 240 Volt mains the heater rating is going to be exceeded.
The anode is a woven mesh and the grid looks to be gold plated. The central cathode can be seen to be oxide coated. The two heater wire loops can be seen on the left.
In this enhanced picture the heater loops are easier to see.
The grid winding and cathode connection on the right.
Looking along the length of the anode. The far end of the anode is a ceramic plug that holds the components in place.
Here the supports holding the horizontal anode are clearer.
The heater wire is very fine and can only be seen under a glass.
The balloon envelope is 50 mm in diameter, and excluding the B5 base pins is 91 mm tall.
Reference: 1043. Type U920 was first introduced in 1932.