... wear-resisting than other plastic self-lubricating nonmagnetic plastic ball bearing: also called together the formaldehyde, steel, are ... generally POM rings , PA66 / PE cage, glass ball/ceramic balls, open. The hardness of POM is better in ... wear-resisting, environmental protection, self-lubricating, absolutely electricity, no magnetic. Resistance to rust. Disadvantage: cannot be used in high ...