The RJ-KIT is a RJ12 cable extension kit that works with all of the Croptiva sensors and devices to extend the length of the RJ12 cables provided with each sensor and device module. Each of the Croptiva sensors and devices come with a standard cable set. The RJ-KIT allows you to expand your Croptiva system or extend the cables connecting optional sensors and devices. The RJ-KIT consists of a 5ft RJ12 cable, a 16ft RJ cable and a 3-way Y cable splitter.