Abstract: A yo-yo with the hubs made of either acetal or polycarbonate is disclosed. These materials allow the axle to be press fit into the hubs of the inertial disks with the capability of adjusting the gap between the inertial disks by rotating the two inertial disks relative to each other while pushing or pulling. The high mechanical stability of these materials result in a tight fit between the hub and the axle even after many cycles of gap adjustments and or axle replacements. The performance is improved by adding a smooth sloped transition at the periphery of lapper disks to the larger gap between the two inertial disks. A knot is tied in the tether approximately 2.0 inches from the periphery of the inertial disks. The knot wedges in the sloped transition, which substantially reduces tether slippage. A finger strap is used to attach the tether to the hand.