Dry Contact Station Single Pack with cale set - The Trolmaster DSD-1 Dry-contact module provides a simple and flexible solution to user’s who want to connect & control devices to the Hydro-X using a “dry-contact” or relay to activate the device. Some equipment requires either normally open or normally closed contact closure in order to activate the equipment. The DSD-1 is the product that you need to control those types of devices. * The DSD-1 plugs into a standard Nema 120 volt 15/20-amp power outlet to provide operating power to the DSD-1 circuitry. Then the user can use any voltage (up to 240 volts @ 10-amps) to connect their control voltage from their equipment to the common, normally open and/or normally closed contacts on the DSD-1. Almost any device that requires a “dry-contact” or relay to activate will work with the DSD-1.