I use the app with the with PT301 Personal tracker; manufactured by Startrack Technology Co.Ltd. imported by alibaba.com Has a few bugs have no way to report them. Has a great real time tracking map feature with 30 second location updates. In Device info, Cant save device name and device phone number, everything else works fine. I keep track my dog on long day and two day hikes in the wilderness, you need cellular service. Once I have his location from the app i use GPS Hiker app ( great app) to go and get him since there are no roads any where I am. He is a trail blazer and we can get separated. Not bad for free app and inexpensive device. Regarding the device compatible with this app. It needs a micro sim for a gsm network; i got an ATT micro sim. In order to work you need to insert sim correctly, slide clip toward hing and lift , insert sim as shown on device, SLIDE clip back on top of sim to lock. Make sure it is locked in! If the sim is a new account or prepaid , set up voice mail or it won.t work correctly. I did this by putting in sim in an ATT phone and dialing 01. Selected std set up.

I like the app. It would be nice if app can also show gps coordinates, as positions on in built app is off by quite a bit.