What makes Sky-FramePlain doors special is the seamless transition between the inside and the outside that is completely flush with the floor. The sliding door glides on floor tracking only 10 mm / 3⁄8" inches wide. The space between the narrow tracks is covered by the same flooring material as the interior of the room, which creates the impression of a smooth transition between indoors and outdoors. Open the doors and you will notice the seamless transition, that is pleasing to the eye and provides a smooth sensation when walking barefoot.