WITH BAY LUGS: 3" with bay lugs. Valterra brand. 4 5 degree clearview fitting with bay hook and bay lug. No need to reattach hose and mess with clamps. Just twist your current bayonet hose adapter on and you're ready to go.
NO BAY LUGS: 3" without bay lugs. Valterra brand. Clear fittings for every application inside or outside the sewer compartment. Clear material allows you to see when it's clean.