Dog goes out, dog comes in — easy as that. When he goes out, the inner clear plexiglas panel and the outer welded aluminum frame swing out. When he comes in, the frame stays stationary and only the plexiglas panel moves. Chew proof and weather tight. 1/4” plexiglass, 12/5” x 17.5” opening. Made in USA. No Next Day or 2nd Day shipping.