This is a standard (size C) unresponsive centre track bearing that will fit any of our yoyos, except the Loop 360. The bearing has a flat surface on which the strings sits, but then rises up at the edges. This ensures that the string sits in the middle of the bearing, not touching the sides of the yoyo or response system. Keeping the string away from the yoyo helps the yoyo spin longer, compared to a regular flat bearing. It also helps with complex string manoeuvres, where there are multiple layers of string around the bearing. Some bearings sit loosely on the bearing seat of the yoyo and can be replaced with the hand. Other yoyos have a very tight bearing seat and requite a multi-tool to remove the bearing. It is not recommended to remove bearings with pliers, because they can be bent or damaged.