Freilauf is a patent drain, that doesn’t allow hair to get caught. The cover has a pole which contacts the drain at a single spot, down in the pipe and is stabilized by magnets (1). This ist the only point where hair might collect. (2). If you step on the lid, once in while during a shower, the pole slips out of its fixture (3) and lifts a little bit of the ground, so the hair get flushed away. (4). If you lift your foot, the lid snaps back in position by magnetic force.
With time, in all drains an ugly film of soap and grease builds up and has to be cleaned. All other drains have edges, gaps and angles that are very hard to clean. The Freilauf is everywhere smooth and round and easy to wipe off. Because the drain is smooth and has no obstacles in the water flow, the flow speed is high and there is less build up. So, the cleaning is not just easier, but also has to be done less often.