The 5U4G rectifier delivers 100 Watts of DC power. It would be used for all types of medium power equipment and was used extensively in 1940's equipment.
The long anode has an inverted V of oxide coated ribbon filament within.
The MWT logo and this exhibit was Made in Italy.
The dual Type designation of U52 and 5U4G printed on the glass. The other side has an etched 5U4G in an octagon - Typical of RCA manufacture.
A closer look at the printed logo and lettering.
The classic envelope is 51 mm in diameter and, excluding the IO base pins, is 118 mm tall.
References: Data-sheet, Data, 1040 & 1043. Type 5U4G was first introduced in 1938. See also1938 adverts.
