VEVOR Linear Rail Guide 15x300mm 2x Slide Rails Heavy Duty 4x Square Type Carriage Linear Motion Kit 300 for 15mm Slotted Bearings

Pretty good for the price. They are a little sticky. I would buy again if i need to.Update: They are not the same height. 0.3 mm off. I had to grind them down to the same height. P.I.T.A. The rail needs to be polished.