Warming: The size S is for flat door or window, which do not need screw, just glue it together. ----***FYI: Package is not included glue.*** Pet Door Interior Door Sliding Door for Cat, Small Dog, Rabbite, Exterior Safety Door with 4 Modes (4 Ways) Locking, Weatherproof Pet Door, Suitable for Thin Window, Door and Wall - Size Small .
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