I am deaf with a recent cochlear implant. I purchased this for my son who has special needs and is unable to get out of bed independently. I have no way to hear him once I take my processor off at night my husband works 24hr shifts (firefighter).) I paired this with my CentralAlert system in my home that I use for its visual shaker alarm clock functions and placed this button on his nightstand. He can easily press this button to wake me to come to his assistance overnight. It provides great convenience and peace of mind. It comes with it's replaceable battery already installed and with instructions to very quickly easily pair it with the CentralAlert base unit. It makes the base unit's bright white LED flash, displays 34;SOS34;, activates the shaker (separate with long cord to allow me to place it under my pillow at night) also makes some audible noise but even with my CI, I can't adequately describe the sound, sorry! (I just got my CI a few months ago) Please be sure to note, this item cannot be used on it's own! It must be paired to a 34;Serene Innovations CentralAlert34; system. It was a little expensive but I've had mine for about 7 months now I love it for its effectiveness, ease of use, durable components and the peace of mind/security it provides!