- Easy to install, simple and generous. 2. very good quality, made from ABS material (the best kind of plastic) 3. big size, bigger size, suitable for many pros fat cats. 4. four main functions. 1, no entry and no exit (fully closed) 2, can be outside and inside (completely open) 3, just in and out 4, just out and not in Medium size: with frame size: H20 * W19 * Th 5.5CM & nbsp; & nbsp; & nbsp; Door cover size: inner height 15.5CM * inner door width 15CM