@JP12,

I will need to check for sure, but I believe that the Y is provided when looking at the longer cable lengths KL400L10 vs KL400L5, as they are not one long chain of lights and instead are two separate rolls. Using other cables is not officially supported under our warranty, but you may find other posts where users have found similar cables that work with our lights. Also, before going down the path of splitting your signal, please verify your model is a KL400 and only supports 1 color along the entire length of strip. Light strips with control over zones must be used with their included cables and controller.