12v convertor adjustable

I put a new Sirius unit into a cutomers car today, that had a shop in FL put the old one in. Basically they tapped of the ignition wire and hardwired the unit.  The new sirius units have a transformer in the cig power adaptor that converts the 12v from cig lighter to 4.6 to 5.6 v.  There was nothing I had on hand to take care of this, so I was looking under the dash to see how they had accomplished this task.  There was a small black box with  a dial on it that you could adjust from 12v all the way down to 2 volts for the output.  Any idea where i can buy something like this at???  Someone in the world makes it, i just need to find out who.  there were no identifiable markings on it whatsoever.

Thanks in advance!

I would look at electronics stores (not Radio Shack, but one dedicated to electronics components)

Ganbatte ne!

i would make it easy on yourself, and just use half of a 12 volt socket splitter.  just cut it in half and hardwire it.  then just plug the sirius adapter into it.   you can hide it all up under the dash.  this is what i am talking about.

https://store.safetycentral.com/doso12voposp.html

here is the adapter that you are looking for though.  i use many of these on the boats at work. 

https://www.powerstream.com/dc7.htm