Product: 10 × SMR84ZZ hybrid ceramic ball bearings (4 × 8 × 3 mm), ABEC-7 Key benefits - High-speed, low-friction performance: Si3N4 (silicon nitride) ceramic balls reduce friction and heating for smoother rotation at high RPMs. - Precision and consistency: ABEC-7 rating ensures tight tolerances and repeatable performance in precision applications. - Corrosion resistance and durability: hybrid construction helps resist rust and extends service life in varying environments. - Ready-to-fit compatibility: compact 4×8×3 mm size fits MR84Z-type housings and is interchangeable with listed model variants. What’s included - 10 pieces of SMR84ZZ bearings - Model: SMR84ZZ (MR84Z type) - Size: 4 mm inner diameter × 8 mm outer diameter × 3 mm width - Rating: ABEC-7 - Ball material: Si3N4 ceramic (hybrid design) - Shielding: ZZ (double metal shields) Compatibility and interchangeable model names - MR84Z type bearings, also listed as SMR84C, SM84 ZZ Z, L840ZZ — compatible where MR84Z-type bearings are required. - Use where a 4×8×3 mm MR84Z-style bearing is specified. Performance and design notes - Hybrid design (steel rings with Si3N4 ceramic balls) provides a balance of toughness and high-speed capability. - Double metal shields (ZZ) offer basic protection against dust and debris while maintaining low running resistance. - Engineered for reliable operation across a range of working conditions where compact, high-speed bearings are needed. Practical applications (examples) - Small high-speed electric motors and micro gearboxes — maintains smooth rotation and reduces thermal buildup. - Camera gimbals, pan/tilt heads, and precision robotics joints — supports precise, low-vibration movement. - RC motors, drones, and other compact hobby electronics where compact bearings and high RPM capability matter. Why customers choose these bearings - Direct replacement for MR84Z-type bearings with exact 4×8×3 mm sizing. - ABEC-7 precision rating and Si3N4 ceramic balls for improved speed and lifetime versus all-steel alternatives. - Pack of 10 provides spares or multiple bearing installations for maintenance and upgrades. Related product - SMR52C ZZ available (2 × 5 × 2.5 mm) for applications requiring smaller MR52C-type bearings. Ordering tips - Confirm required bearing size (4×8×3 mm) and shield type (ZZ) before purchase. - Check compatibility with MR84Z or listed alternate model numbers (SMR84C, SM84 ZZ Z, L840ZZ) if replacing existing bearings.