OBDII wireless reader

any recomendations for a wireless OBDII reader to pair with a spare iPhone?
I'd like one that "sleeps" when not in use so that I can leave it plugged in all the time.
Reviews on Amazon are all over the place and hard to gauge true reliability.
I'm not interested in a scan gauge right now since I already have the extra iPhone and would only need the app and reader.

Thanks

 

I've used several different ones over the years but I currently use this one. Works very well so far and being small you can leave it plugged in all of the time and it never gets in the way. (it sleeps and wakes up automatically too)

https://www.scantool.net/obdlink-mxwf.html

 

I currently picked up the LX version.

 

I like the price of the LX version better. However it uses Bluetooth to transfer the data to your phone. When driving I use my phones Bluetooth for hands free calling with the trucks stereo. Can it do both, or do I have to choose?