
Bought while I was upgrading my 3D printer to linear rails. As with any linear guide components you buy online (except Hiwin or Steinmeyer), you'll have to disassemble them to clean them of shipping grease and re-grease them yourself. High-quality ball bearings and mounted on a Chinese rail without play and smoothly. Although many use silicone grease for these bearings, I would recommend using machine oil as it is a roller bearing. Using a good medium weight motor oil also works great which I've printed for about a hundred hours with no problems.

Iverntech 400Mm MGN12 Linear Rail Guide With 2 Black Stainless Steel MGN12H Carriage Blocks For CNC Parts And 3D Printer Upgrades
8 Review

Iverntech MGN12 700Mm Linear Rail Guide With MGN12H Stainless Steel Carriage Block For 3D Printer And CNC Parts
11 Review

Iverntech MGN12H Linear Rail Guide With Stainless Steel Carriage Blocks - 700Mm Length For 3D Printer And CNC Machine
9 Review

Upgrade Your Furniture With Happybuy 10 Inch Stroke Electric Actuators - Heavy Duty 6000N DC 12V With Mounting Bracket For Recliner, TV Table, Lift, Massage Bed, And Sofa
9 Review