Dakota Alert 2500 Ft. Wireless Doorbell Set The longest-range doorbell in the store. Perfect for homes, shops, stores, or large properties. Powered from C relay output to trigger external alarms or bells. Supports multiple push buttons and receivers and easily integrates with the 2500 ft. driveway alarm products. 4 tones to choose from and adjustable volum You can designate transmittors to up to 4 different zones.