Trolmaster Extension Cable Set. RJ12 (ECS-1) comes complete with another 16ft cable, Y-splitter and 4 ft cable.

TrolMaster modules and sensors all come complete with a RJ12 16ft cable, Y-splitter and RJ12 4 ft cable to connect to the TrolMaster Hydro-x controller. When connecting modules that are farther apart, you can use the Extension cable set ECS-1.