TrolMaster modules and sensors all come complete with a RJ12 16ft cable, Y-splitter and RJ12 4 ft cable to connect to the Hydro-x. When connecting modules that are farther apart, you can use the Extension cable set ECS-1. The ECS-1 comes complete with another 16ft cable, Y-splitter and 4 ft cable. Package Includes:  1 x Male-to-Male 16ft RJ12 Cable 1 x Male-to-Male 4ft RJ12 Cable 1 x RJ12 T-Splitter  

The ECS-6 extension cable is simply a 16 ft extension cable to use with the WCS-1 moisture contet sensor. It has a male and female end and can extend the distance between WCS-1 module and the sensor probe.