The DZ-1008A Relay Module can be used with the DZ-1000 Switch Machine or separately. The Relay Module plugs directly into the DZ-1000 Switch Machine and provides a SPDT relay output capable of handling 10 Amps. When the Switch Machine is switched, either by remote or manually, the relay also changes. Used separately, the DZ-1008 Relay Module can be driven by the DZ-1011 Block Signal Detector and used to operate many accessories. . DZ is a custom manufacturer. Items are not usually on back order but are produced in small batches and are not always available as open stock to ship immediately. Items are shipped to the oldest order first as they are received. Z Stuff is a Limited Quantity Specialty Item Manufacturer. Items may be produced in low quantities with very little or no extra stock being manufactured in a production run. To best insure delivery of items we suggest that you place a back order. Easy connection to DZ-1000 Switch Machine, Provides 10Amp SPDT relay contacts, Can be used with DZ-1011 Block Signal Detector to operate other accessories, Long-life red and green LED indicators.