This is the RAL-6, also designed by, and in this particular one, built by RCA. It is nearly identical to the RAK with the exception of its frequency range which is from 300 Khz through 23 Mhz, an added "Frequency Vernier", and an Audio Broad/Sharp switch. Power requirements and size are identical, and weight is a little less than the RAK. I used an RAL-7 for many years as my main station receiver and thoroughly enjoyed its sensitivity, selectivity, and marvelous stability. I have another one now and really enjoy using it. There is a certain sense of "transparency" when listening to signals on the air with it. This particular RAL-6 originally was used on the US Navy Fleet Submarine, the USS Pintado at one time, and its meters, in this photo, are not original. They were replaced with original meters when the receiver was restored and now it is being used by a fellow regen user in Tennesee. Below is its nomenclature plate.