The body of the RM-315 radio is a rectangular box with rounded corners, made of a sleek plastic that is vibrant maroon. The front face of the radio is recessed with a thick edge that angles inward and is split into two sections. The eight by eight lattice grid of the speaker grill takes up slightly more than half of the right side, underneath which there is thin beige fabric. There is a large off-white dial centred on the left half of the front face. The dial has a handle and a dot indicating the selector. On a slightly elevated circle, numbers representing radio channels are carved and painted around the upper half of the dial, with the word “ROAMER” on the lower half. Underneath this dial there is a small white knob with grippy raised lines around the side.

The beige back panel is made from a thin fiberboard that is loosely attached by one screw in the upper left corner. The metal, wires and glass tubes of the interior parts can be seen through two oblong cutouts in the middle of the panel. Underneath these cutouts there is a product sticker that has Viking branding, Eaton CO. Limited patent information and the serial number. Notably, this label says the finish is green, indicating a potential production error or that this isn’t the radio's original back panel. To the right, there is an inspection sticker with three faded red circular stamps. Above the cutouts there are two black squares with information about the power supply and tube layout. A long white electrical cord extends from a cutout in the back panel. Above this, the blue cased wire radio antenna is short and extends above it from a circular cutout labelled “external antenna”. It should be noted the bakelite can change colour over time due to exposure to light. The cream colour of the knob, dial and electrical cord were likely a brighter white when the RM-315 was first produced.