1This linear rail guide is made from quality bearing steel material, which has high hardness and durability. 2With professional and premium guide rail and stopper, this linear rail guide is sturdy and durable. 3The linear rail guide ensures high accuracy and stable performance, small and lightweight, suitable for most automation equipment. 4Equipped with two rubber stoppers on each side of the linear rail, it can prevent the carriage block from falling out 5This linear rail guide is suitable for Ender3/Corexy/Delta Kossel 3D printer upgrade and CNC machine. Item Type: Linear Rail Guide Material: Bearing Steel Model: MGN12C Rail Height: Approx. 6.5mm / 0.25in Rail Width: Approx. 12mm / 0.47in Leading Thread: M3 Guide Hole Spacing: Approx. 20mm / 0.78in Length (optional): Approx. 100mm / 3.93in, 150mm / 5.9in, 200mm / 7.87in, 250mm / 9.84in, 300mm / 11.81in, 350mm / 13.77in, 400mm / 15.74in, 450mm / 17.71in, 500mm / 19.68in 1 xLinear Rail Guide