About Ghost Teeth 2.0 Dual - axis Linkage: The 6703 + R188 dual - bearing system enables the inner ring and outer teeth to interact with each other. Steel Balls Insertable: The internal cavity can hold 3 to 12 5mm steel balls. When rotating, clear marble - like sounds will come out through the sound - emitting holes. Industrial Machinery Style: With meticulous design and fine craftsmanship, it satisfies the enthusiasts of gear machinery. CNC 3D Chamfering Process: The tough saw - tooth shape comes with a comfortable toggling hand - feel. NXEDC's Viewpoint Compared with version 1.0, version 2.0 modifies the symmetrical saw - teeth into oblique saw - teeth and adds a rounded chamfer design, which indeed improves the rotational hand - feel. The sand - blasted surface treatment process is quite durable. After playing with it for a long time, not many marks were left.