The Rhino Elbow and 4-in-1 Adapter with Swivel Bayonet Fitting makes it easier to connect to dump stations. It fits securely into four sizes of dump station inlets: 4 In. NPT, 3. 5 In. NPT, 3 In. NPT and 3 In. slip fitting. The elbow is clear, so you can see when your sewer hose is completely done draining. It has a built-in gasket for an odor-tight connection. The swivel bayonet fitting makes the elbow compatible with any lug fitting and allows it to rotate 360 degrees, making it easy to connect. For storage, the elbow detaches from the 4-in-1 adapter and fits into a 4 In. square RV bumper.