MGN12H 300mm Linear Rail Guideway Rail with Block for 3D Printer CNC Machine Features: Made of metal, sturdy and durable. Compact and lightweight, ideal for small equipment. Adopting 4 point contact design, it can bear load from every direction. Designed with ball retainer, which allows interchangeability in the case of small precision. Widely apply for 3D printer, CNC machine, automatic equipment, precision measuring equipment, etc. Specifications: Material: Metal Rail Size: 30 * 1.2 * 0.8cm/ 11.8 * 0.5 * 0.3in Rail Weight: 196g/ 6.9oz Block Size: 4.5 * 2.6 * 0.9cm/ 1.8 * 1.0 * 0.4in Block Weight: 50g/ 1.8oz Package Size: 33 * 6.5 * 2cm/ 13.0 * 2.6 *  0.8in Package Weight: 283g/ 10.0oz Package List: 1 * Linear Rail 1 * Linear Rail Block