Material: Internal & External Ferrules: Ceramic（Silicon Nitride Si3N4, Zirconium Oxide ZrO2） Rolling Element: Ceramic Balls Holder: Nylon, Ceramic, Teflon Specification: Inside Diameter ≥8mm Rolling Bearing Maximum Precision: ABEC-5 Features: anticorrosion, high temperature resistance, antimagnetic, oil free and selfoiling Application: Special working conditions in the field of chemical industry, petroleum and food etc.