Three radios will fit the opening. The standard radio has five ivory pushbuttons and is curved on the bottom opening. There is also a standard radio with 5 chrome pushbuttons. Standard radios have 6 tubes. Deluxe models have 8. The deluxe has 6 chrome pushbuttons. The volume and tuning ***** are a different style on the deluxe model. The plastic lens on the deluxe model is also different on the deluxe model with the word Ford in the middle at the bottom. There were at least four different makers of these radios which can be frustrating when you need repair parts. I associate the deluxe radios with 5 star cabs. The radios that are square on the bottom with black pushbuttons are for 1951 cars only. The 51-52 standard and deluxe radios fit 49-50 cars.