General description VEVOR high-quality SBR linear guide rail set includes 2 guide rails and 4 slide blocks, designed for high precision and low noise operation. The durable aluminum guide rails feature precise hole diameters and distances, while the SBR slide blocks utilize ball bearings for smooth and unobstructed movement. This set is ideal for various automated machines and DIY projects, including CNC routers, 3D printers, and laser engravers. Technical specifications Model Number: SBR12-C 1000L Slide Block Model: SBR12UU Guide Rail Length: 39.4 in / 1000 mm Shaft Diameter: Φ12 mm Dynamic Load (per block): 372 N Static Load (per block): 549 N Material: High Carbon Steel & Aluminum Mounting Hole Distance A: 1.1 in / 28 mm Mounting Hole Distance B: 1 in / 26 mm Slide Block Size (L x W x H): 1.5 x 1.6 x 1 in / 39 x 40 x 27.6 mm Product Dimensions (L x W x H): 39.4 x 2.5 x 1.2 in / 1000 x 64 x 29.6 mm Package Size (L x W x H): 43.3 x 2.6 x 3.9 in / 1100 x 65 x 100 mm Net Weight: 7.5