At first I had a hard time getting the sim to work. I finally got a standard T=Mobile sim and it works with that. The watch rings loud and it has a speaker button so you can hear the other person but it does cut out and you can't get the whole sentence. You can recieve texts no problems but sending them is hard because the keys are so small on the Lcd screen. My video recorder doesnt save to the file on the sd card and the blue tooth doesnt work either. I will work on those issues and see if I can get them to work. It a fun little gadget but not for a main cell phone more of a show off and talking piece.