Silent Call Strobe Lights can be used with a variety of alerting devices and systems, including alarm clocks and the Silent Call Sleep Alert/Charger. The strobe alerting light are available with a pin-jack or transformer, making them easily adaptable for a number of uses. Super-bright alerting - 110 candela. 24-volt. 318 MHz. Easy to install and simple to operate. 5-Year Manufacturer's Limited Warranty. One strobe light.