This Linear Guide Rail kit features SBR20-300/600/1000 mm rails, three ball screws, 3 sets of BF/BK 12 supports, and 3 flexible couplings. This bearing rail is constructed with high hardness steel material. The rust-proof and antioxidant surface treatment provide smooth running. The linear rail and ball screw kit is widely used in automation machinery such as CNC routers, lathes, machine tools, bending machines, laser welding machines, etc.