This is the new BallBearing as comes standard with the new YoYoFactory in Size C. Now available as replacement for any Yo-Yo that uses the size or Size C Yo-Yo Bearing.
A stainless steel 8 BallBearing Narrow Size C .
A Chrome Steel 8 BallBearing size C "Flat".
A Ceramic Concave stainless steel 8 BallBearing. These are replacement bearings with Concave profile and available in ILYY (metric) Size.