... ,ToleranceLevels of our skate bearings include ABEC-1, ABEC-3, ABEC-5, ABEC-7 and ABEC-9. ABEC-5 is the most favorable due to ... nylon retainer. 5,Materials of Ball and RingThe bearing rings and ball are made of such materials like chrome steel, stainless ... ", our products enjoy a wide popularity for exquisite technology, elegant designs, practical styles, high quality and reasonable prices. Most of our ...