These easy to use caps can make your do-it-yourself gardening projects much easier. Have you ever needed to cap off one end of a irrigation fitting in your hydroponic garden? You are left searching for some sort of leakproof plug. Here is your answer. The Hydro Flow? EZ Pull? End Caps are made from tough, flexible vinyl. They are easy to push on and pull off, yet provide a secure, leakproof fit.