Features The cnc linear guide and linear bearing are made of high quality carbon steel, and the bearing block is made of aluminum alloy, sturdy and durable. Industrial-grade standard SBR block with high precision. Standardized processing, ideal for guide rail positioning. Aluminum alloy support rail with pre-drilled holes for ease of mounting. Perfect for your DIY CNC routers, mills, lathes. Product features: The cnc linear guide and linear bearing are made of high quality carbon steel, and the bearing block is made of aluminum alloy, sturdy and durable. Industrial-grade standard SBR block with high precision. Standardized processing, ideal for guide rail positioning. Aluminum alloy support rail with pre-drilled holes for ease of mounting. Perfect for your DIY CNC routers, mills, lathes. Product Specifications: Material: High carbon steel, Aluminum alloy Model: SBR 12 Color: Silver Rail shaft length: 200 mm Rail shaft diameter: 30 mm Housing dimensions: 40 * 40 * 26 mm Weight: 991 g Package contents: 2 * Linear slide 4 * Bearing seat Caution: For manual measurement, an error of 1 to 3 mm is allowed. thank you for understanding. Package List