Abstract: The flange apparatus provides a positive seal for an appliance tube which enters a junction box of a travel trailer, motor home, or the like. The union of the apparatus is fitted coplanarly to the exterior wall of the junction box. The first and second segment overlap the opening in the junction box, further ensuring a complete seal. The second flat bottom of the second segment abuts the frame of the box exterior wall, further ensuring a complete seal. The orifice of the apparatus is provided in more than one size. Each size of the apparatus orifice conforms to a particular appliance tube size, further ensuring a complete seal per application. The slot of the apparatus aids in insertion of the apparatus into the exterior wall and in the insertion of the tube into the apparatus, then collapses upon itself to fully seal.