I put one on my house boat and it worked pretty good. Has an antenna you mount up high outside and then coax cable to a reciever/power module and then coax to an internal antenna. If you have no service, it will not help you at all. If you have 1 or 2 bars or you have to go outside to get service, then they're great. Look up Wilson electronics and make sure you get one that is for the band of phone you use. There are different models for 3G, 4g, etc... Or you'll need a 5 band to cover all options.