4G - “What makes SkyAngel911FD different?” SkyAngel911FD has no monthly service fees of any kind. Once you buy the device you will never pay to use it. SkyAngel911FD is similar to an “OnStar" for Emergency Situations. This premier alert system provides freedom with security. With the touch of a button, you can talk with 911, anytime, from virtually anywhere there is cell service. Other products like a traditional Personal Emergency Response System (PERS) only allow you to call for help at home. This allows you to take it outside and down the road. Unlike a PERS, SkyAngel911FD works both indoors and outdoors to ensure anyone has peace of mind knowing that help is always available. SkyAngel911FD will use any available cell tower so you don't have to worry about coverage. (Cell coverage is not available in all areas - this works similar to a cell phone)