Sealed bearing provides quiet operation and long service life. The seal keeps dirt out and reduces maintenance needs. CNC machined with a precise tooth pattern. Delivers accurate chain engagement, smoother operation, and reduced wear. and construction. Built for reliability and durability under regular riding conditions. Designed to fit square hole chainrings. Ensures a secure, accurate fit with compatible cranksets. Applications and use scenarios Mountain biking and trail riding: worn components on bikes with square hole chainrings to restore smooth pedaling and reduce chain noise on rough terrain. Urban commuting and daily riding: upgrade to a sealed bearing solution to improve reliability and lower maintenance needs. Bike restoration or custom builds: suitable for projects requiring compatibility with square hole chainrings.