Skylink VS-433W Glass Door Window Vibration Security Alert Alarm Safety Protection Sensor | Affordable, Easy to Install DIY Accessory for SC Series Systems NO MONTHLY FEES and easy DIY (Do It Yourself) installation VIBRATION DETECTION, shock or impact to your RV, boat, car, safes and more. Compatible with Skylink security systems, SC-10W, SC-100W, and SC-1000W UP TO 100 FOOT OPERATING RANGE in open area. LIFETIME SUPPORT - Toll free 1-800-304-1187, support@skylinkhome.com