The Quick Seal Mainline Entrance Fitting is the first mainline entrance fitting that actually is designed to fit polyethylene tubing. The fitting has the flexibility to fit around tubing that is not perfectly round. This fitting is not designed for use with black plastic water line. So simple to install! just drill a hole in the top of the mainline, insert the gasket and attach the fitting. Done! then you can easily attach the Quick Seal Mainline Entrance Fitting to your lateral line anchor (hooked connector).