Introducing the NEW FZ Reverse Hybrid R188 bearings in Si3n4 and Zr02. These bearings are constructed of ceramic races, high quality PEEK retainer and 9 Stainless steel balls. These bearings provide a unique feedback and above average spin time for a full ceramic.Delivers a pleasant sound. Can easily be cleaned with 90% ISO and dried thoroughly wit hair dryer. All reverse hybrids are tested before shipping for quality and performance. There are no exchanges or refunds on this item.