What device to stream music via BT from Pro to radio through 3.5mm jack?

[Shohan]

I have an older radio in my car. It works and I see no reason to buy a new radio with BT just to listen to music. It does have RCA Aux inputs in the back which I have connected to an RCA to 3.5mm stereo jack cable. I used this to play my iPod in the car. What I'm looking for now is basically a bluetooth receiver that I can plug into this cable and pair with my Pro in order to stream the music. I've found plenty of transmitters, like the MSI Bluetooth Music Audio Transmitter FS320, but I'm not sure if this will work in reverse. That may sound like a stupid question, but the only other BT device I have is my earpiece.

So how can I go:

Pro >>BT>> BT Receiver --3.5mm/RCA Cable-- Radio