The customer contacted us because they had no windows in their kitchen and it was difficult for air to get through, so they wanted to replace the back door with one that would let air in. When we asked, we found out that the back door was a type with glass on the top and a panel on the bottom. When we measured it, we found that it was too narrow to be replaced because it was outside the range of current standards. Therefore, we suggested replacing the bottom panel with a glass louver window. By turning the lever, the glass opens and closes up and down to allow air to pass through.