Carlson Pro Pets Wall Mount Royal Pet Door, Large Our bi-parting door that is the best of the best with proprietary v-cam hinge system and commercial grade magnetic gasket for a proper seal every time Training tool provided to acclimate your pet to its new door Features security lock and quick attach stainless steel security panel Incredibly easy installation, expandable tunnel in wall mount version fits walls from 4.75 Inch to 7.5 Inch with no cutting of the frame required Large Opening Dimension 18"l x 14"w Note: Please refer the user manual below for installation