Abstract: A product includes a panel that can be used in place of a door in a cabinet. The dimensions of the panel are such that it covers the opening in the cabinet that was covered by the cabinet door. A pet door (e.g., an opening with a moveable flap or cover) is installed in a precut opening in the panel. A litter containment system (which includes a litter box or something else of similar purpose) can be placed inside the cabinet. A pet (e.g., a household pet such as a cat or dog) can reach the litter box or the like through the pet door. The panel includes features that allow it to be readily installed, removed, and re-installed, so that the pet owner can easily reach, remove, empty/clean, and replace a litter box or the like that is inside the cabinet.