The lift is the flexible one. On its own it gives a single cat a ramp to climb and a hammock to lounge in, a complete little perch in one piece. Drop it into a larger layout and it becomes another stop on the route for a whole crew of cats.The modular design lets you set it up however the wall wants it, ramp angled up or down, positioned to the left or the right. It works with studs at 16 or 24 inch spacing and goes up without fuss.