Fits 1 inch PVC pipe with an Outside Diameter of 1.315 inches. Add a perpendicular pipe to your project without cutting or taking apart your PVC frame. Based on Snap Clamp design and function, this tee fitting allows you to easily install a 90 degree extension onto your PVC project. Great for adding strength to long spans of pipe, adding a section of pipe to your box frame or creating a cross-brace for your project.