Review on Effortless Car Control: PolarLander Universal Wireless Steering Wheel Controller for Music, DVD, GPS Navigation, and Radio - 4 Key Remote Control Buttons in Sleek Black by Kevin Hawkins

I'm using them with an Android head unit; Pairing is really easy and reliable. The units themselves are not very good. Within 2 weeks of purchase, the volume/search button began to work intermittently (and the mute function never worked). So I adjusted the volume and looked for the GPS/Phone button. This worked for another 2 weeks and then this button worked intermittently. So I swapped the batteries on both. The buttons have been working flawlessly for a few months. Unfortunately, once you pop the knob to put in a new battery, it tends to pop back open (my pickup would blow the insides out with a significant dent). So I finally put the volume/search buttons on the GPS/phone board and glued the device insanely tight. Everything has worked great for the past few weeks, including the mute function, which never worked on the board with the volume/seek button. When the battery dies, of course I have to replace everything. But because of the cheapness and convenience, I'd make the hassle again. 3/5/21: The block I glued doesn't work anymore. I'll try another pair to see if they work better and then give up.