This is a custom made Bluetooth adapter for old (late 60's - late 70's) Becker stereo radios with internal or external amplifier with two speakers output (Stereo).

It will allow streaming music from your Bluetooth device (phone). Picture of the actual device is in the first slide.

Works for the STEREO Becker radio as follows:
If still in doubt, look at the back of your radio. It should have the round cover (sometimes black, sometimes white) with 4 metal pins that plugs into the radio 7pin outlet.

For mono radios (one single speaker output) you need a different adapter, with 6pins; this one for sale here it will not work. See here the mono (6 pin) adapter: https://www.ebay.com/itm/134712120942

How is this Bluetooth adapter works on a 50 years old radio:

The designers of the time did not had an idea about Bluetooth but they were smart enough to provide a DIN plug on the back for Input/Output of the audio signal.

The DIN plug on the back can be used to insert this adapter  to stream audio from your Bluetooth device

Open the round plug in the back of the radio, insert the adapter and you are done. You have to do that only once, when you install it; after that every time the radio is ON the Bluetooth will be also present.

The adapter is routing the signal from the Radio or from the Bluetooth (Phone) source based on the audio signal (if is present or not) at the Bluetooth device (Phone).  

Audio volume can be adjusted either from the Phone or Radio.

Connection is established every time the radio is turned ON and the pairing Phone is present.

If you buy it at the same time with one of my radios, I will ship it along with the radio and refund this shipping cost.

Bonus:
A microphone for hands free communication. The feature works decent but not great (it does not have advanced features to customize the sound level); it is not a guaranteed. 
You do not have to connect (no need to insert the jack in the adapter plug) the microphone if you do not use it.


What you receive:
- Bluetooth adapter - for Becker Stereo with 7 pin connector
- Microphone
- Instructions sheet


Happy Motoring!