This listing includes four SBR12UU open linear bearing blocks designed to ride on 12 mm linear guide rails. Each block is an opentype bearing block that accepts 12 mm guides and provides smooth linear motion for a variety of applications. The open design facilitates installation, maintenance, and lubrication along the rail. Key benefits Four blocks in one set, enabling multiple axes or replacement needs without repeated . Open linear bearing block design that allows easier access for lubrication, inspection, and maintenance. Precise, reliable motion on 12 mm linear guide rails with consistent alignment along the axis. Broad compatibility with standard 12 mm linear guide systems across brands, helping to upgrade or refresh existing setups. Key attributes Model: SBR12UU Type: Open linear bearing block For: 12 mm linear guide rails Package quantity: 4 pieces Compatibility: standard 12 mm linear guides Size: designed for 12 mm guide rods Material: not specified in the listing Performance: intended to provide smooth, dependable linear motion along 12 mm guides Use cases and applications 3D printer axes (X, Y, or Z) where open bearing blocks are preferred for easy maintenance and accessory installation. Small CNC machinery or milling/router axes requiring reliable 12 mm linear guidance. Automated equipment, packaging lines, or assemblyline slides that use 12 mm rails for smooth, repeatable motion. Notes This set focuses on compatibility with 12 mm linear guide rails and the open bearing block design. Material details are not specified in the listing, so refer to the product page or supplier for exact construction materials if needed.