It confines your pet safely using an upper/lower locking system. Plus, the gate locks automatically when the door is released at 45?. Because the Expandable Walk-Thru Pet Gate is designed without a U-shaped frame,itllows you to walk through easily and safely when used at the top of a stairway opening.itttaches securely to wall surfaces/openings from 31.5? to 47.2? wide (Gate Door expands up to 47.2? wide) and fits beautifully in any home interior!Its beautiful hardwood construction complements Richell's other fine wood pet products. Available in a rich, dark finish ? Coffee Bean. Permanent assembly required. Designed by Richell Corporation, Japan. Gate Door locks automatically when released at 45?. Hassle-free design allows safe and easy passage. Beautiful hardwood construction. Assembly requires attachment to wall surface for safety.General Product Information: Recommended for medium size dogs 17.6 to 44 lbs. (8-20kg). Instruction manual included. 1.9" space between wood spindles. Wood spindle size is 5/8?. 1.75" space between floor surface and bottom of Gate Door.Made from eco-friendly, sustainable bamboo.