Carlinkit Mini Ultra, I have three of them purchased at different times for $39 to $49 depending on Amazon's mood.
Excellent all the way, immediate connection, no issues so far. First one bought last year, used day in and day out.
The only complaint is the thing is so long range that my phone connects to it when the kid turns in the driveway, AND sometimes it can be really sticky (with Android). Meaning - if the car outside is on accessory, my phone picks it up and connects, and even if I disable Bluetooth the blasted thing manages to reactivate it back. Or could be a setting in my phone, so I don't know who's the culprit here