SBR20 Linear Rail Kit: Includes two 78.74 in (2000 mm) linear rails and four slide blocks. It is compatible with cutting machines, grinding machines, milling machines, drilling machines, and other equipment Rust & Corrosion Protection: Crafted from high-hardness carbon steel shafts (HRC5866) and aluminum alloy blocks and supports. Each linear rail is coated with a more than 10 m electroplated layer to resist rust and corrosion, even in humid basements Silent & Smooth Sliding: Built-in ball-bearing slide blocks deliver quiet, low-friction motion while gripping the shaft tightly for stable linear travel. Less noise, less wear, more precisionevery time you move High Precision, No Deviation: Feature a 0.10.22 m surface finish and 5 m straightness, paired with precise hole diameter and spacing, this linear slide rail set ensures easy installation and repeatable positioning, even over long travel distances Installation Made Easy: No extra installation tools are required