Make Life More Easier, no longer the all-day door opener for pet, owner work in peace. Great freedom to pet, they can go in and out on their own. At the first using, just training them to go through it is as simple as holding treat on the other side of it of the door. Magnets along the bottom corners of flap that helps with pulling the flap back original position; and the magnet is strong enough to pull the door closed without being too strong to deter pet from pushing through it. Two slide-key in side to lock door, can be locked from the outside or the inside; Sturdy dog screen door resist pets paw, inner flap with screen keep bugs out; you can install in anywhere screen area, like balcony, garden, screen porch, screen window. Size Information: Outside frame size: 42*37cm ; perfect for medium to large dogs. When you install, the ideally the flap opening height should be an inch or two above the dogs shoulders, it is also decided by your dog size.