100mm MGN7 Linear Rail Guide with 7mm Width & MGN7H Carriage Block - High Precision Linear Motion System for 3D Printers, CNC Routers, Laser Engraving Machines - Perfect for DIY Projects and Industrial Automation

Cheap, yet actually smooth! They say they that chinese rails are always sticky and/or rough, stuffed with thick factory grease. These appear to be an exception. It arrived sealed in a sealed package with a light oil, and came with a ziplock bag with a few extra bearings (which appear to be slightly larger than standard chinese mgn9 bearings, which I take as a sign of quality, but be aware). They run pretty smooth and will slide down the rail by themselves (as opposed to some other cheap rails...). Overall, if you're looking for functional, yet cheap linear guides, these are them.