Half of the cube’s edge pieces have small spring-loaded latches that press into the center piece, and when you twist a layer into place, these latches lock into the center piece, preventing you from turning the layer back. This mechanism makes the cube a bit slower to turn than a normal cube. When you turn a layer, it clicks when the latches snap into place. In return for the slightly slower cube, you get a tricky and fun challenge that requires more of you than the usual Rubik’s cube.
Below you see a picture of how the locking mechanism looks like in the core of the cube:


Gary Williams (verified owner) –
The puzzle mechanism is great, and I really enjoyed solving it. However, mine arrived with lube stains on the stickers. The center caps are very loose and I’ve lost one after one solve. The stickers have also started to peel after one solve.