If you have looked at any general purpose sensors or security sensors, you'll notice that they can't handle much current. The Double Pole Double Throw (DPDT) Form C Heavy-Duty Dry Contact Relay Module is a unit ideal for load switching, dry contact, latching output, reverse polarity, line seizure, and other uses for higher current devices. DPDT essentially means that this contact has two separate poles (or contacts) and can throw (or make) electrical contact with two separate stationary contacts to turn them on or off. You can use it to turn on multiple devices during alarm condition, trigger a 12VDC device (such as a siren) and a 120VAC device (such as a floodlight), trigger an alarm or silent alarm while disconnecting the electromagnetic door locks or to allow the two separate sets of contacts to work together to switch up to 8A of current for heavy-duty work loads A built in red LED light indicates when the relay is energized for quick reference. This product operates via 6/12/24 VDC power, programmable by on-board jumpers. What's Included # Double Pull Double Throw (DPDT) Form C Heavy-Duty Dry Contact Relay Module # Mounting tape # Owner's manual