Camco 3" Gate Valve w/3.5" Clear Extension & CapCamco 3" Gate Valve with 3. 5" Clear Extension & Cap The Camco 'Ready to Use' RV Gate Valve with Built In Clear Adapter is a backup gate valve that provides a quick fix for leaky valves. The 3 inch long clear adapter attaches to your RV's sewer outlet and lets you see when the tank is empty. The gate valve features (4) bayonet prongs for easy hookup and fits all 3 inch sewer fittings. Includes a cap for a leak free, odor tight connection. The product