Skylink 4B-434W Security Keychain Hand Held Remote Control Transmitter | Affordable, Easy to program DIY Accessory for SC Series Systems. NO MONTHLY FEES and easy DIY (Do It Yourself) installation Compatible with Skylink security systems, SC-10W, SC-100W, and SC-1000W UP TO 100 FOOT OPERATING RANGE PRECAUTIONARY MEASURE activate the Skylink Alarm or Alert System in case of an emergency or threatening situation LIFETIME SUPPORT - Toll free 1-800-304-1187, support@skylinkhome.com