What is it? Our Tube Bulk head connector is made of safe,non-toxic material (Polypropylene), which allows users to connect and disconnect quick and easy without the need of any other tools.It is used to mount hoses through any flat surface! It fits standard tubing OD 3/8" Copper, CPVC, PEX and PVC tubing for most RO systems Where to use it? Applications include RO system, beverage dispensing, refrigerator ice maker Water Line Kit, coffee machine etc. This quick connect fitting is perfect for using in a plastic container with flat walls or any flat surface!. These give the setup a professional look. This will take the headache out of an water filter installation How to use it? the top is detachable when unwind the nuts,the nut on the bottom will fully unscrew from the fitting. It is then basically a bolt and nut, with a hole thru the bolt. The head of the "bolt" has a 3/8"hole in it with a catch mechanism to hold a piece of 3/8" OD tubing like used for a refrigerator ice maker. Just drill the hole and screw these bulkheads on. To remove, just push in the outer circle on each end and pull right out. You need to make sure the tubing is cut squared to insure no leaks. Be sure you cut the tubing even and straight, without crimping it. Then insert straight, and all the way into the connector. If it's crooked, or not inserted all the way, or crimped, it may leak What you will receive? Bulkhead adapter x5