The Y2 DualA Yellowood Fingerboard wheels feature a Shore 60D durometer which gives you the perfect balance between grip and slide. The wheels have a diameter of 7.6mm, and use Yellowood's dual bearing system. The dual bearing system has more contact with the truck's axle; this makes the wheels more stable, and even prevents jamming. The DualA wheels use closed ABEC 7 bearings that are lubricated to have a better roll. We recommend you use these wheels with Y-trucks as their dual bearing system makes for a perfect fit. These will not work on Black River trucks.