Serene RF-200 is a Cell Phone Ringer/Flasher with a USB Charging Port that can be used to alert you to incoming calls, SMS messages, Skype™ and FaceTime™ calls, as well as landline calls and WEA (Wireless Emergency Alerts) when paired with a compatible cellphone. It features a missed call indicator light, a built-in USB port for charging your cell phone, and a bed shaker jack for connecting an optional bed shaker.