Corona 203, ca. 1936
Tube complement: 6D6 RF, 6C6 detector, 43 audio output, 25Z5 rectifier, K55C ballast tube.
Approximately 10-3/8 inches / 264 mm wide.
The "volume" control is actually an RF gain control. It is wired in a manner quite different from the interstage audio level control that became so common in later years. One side of the potentiometer is connected to the cathode of the RF amplifier. The other side is connected to the antenna. The wiper is connected to ground. As the pot is turned clockwise, the wiper moves away from the antenna end (reducing the shunting of the antenna to ground) and toward the cathode (increasing the stage's gain).
I've been unable to find much information about this radio, or about the Corona company in general. The radio's date above is only a guess, based on tube types used and general chassis appearance. It looks very similar to the Aetna Model "J" (Machine Age to Jet Age vol. 2, Mark V. Stein, p. 55). On page 336 of the same reference, there's a somewhat different looking "Crusader" brand radio that uses the identical dial. Apparently there was a manufacturer out there in the mid-1930s that churned out a bunch of these simple, cheap radios under different brand names.
Notice the unusual wooden back.