The 5AR4 is a compact high current full wave rectifier for high current small equipment use. This exhibit is branded Ruby and Fender and belongs in Rob's Fender Deluxe Reverb Amplifier.
The Fender logo and Made in China. The other words are Full Wave Rectifier and 5AR4 / GZ34.
The X shaped anodes for good head radiating capacity.
The wide glass tube envelope is 32 mm in diameter and, excluding the IO base pins, is 70 mm tall.
References: Data-sheet, 3002 & 1040. Type 5AR4 was first introduced in 1952. See also1952 adverts.