RM1605-300/400/1200mm Ball Screw & SBR20-300/400/1200mm Linear Rail Kit with SBR20UU Block, Nut Housing, Coupling, BK/BF12 Support - High Precision Slide Rail Ballscrew Set for 3D Printers, CNC Machines, DIY Projects - Perfect for CNC Milling, Laser Cutting, and Automation Equipment