High Quality Material-- Solid steel, chrome-plated metal stamping process, anti-rust anti-corrosion ensure sturdy and durable, double wheels are made of nylon, will not scratch your beautiful door. Easy Installation-- Two assembly installation options, adjust the position of the roller to fit your door panel. Mount to the wall with screws, the door and floor do not need grooves. Safety Design-- Smooth polished chamfered edges and flat bottom design protect your beautiful floors and your family from damage, and internal ball bearings ensure quiet work. Adjustable Design-- Feel free to adjust, The rollers can be adjusted to meet your distance needs, after adjusting screw it, it can run smoothly and silently. 24 Hours Online Customer Service-- If you have any questions, please feel free to contact us by email, we will provide professional service for youFor your satisfaction.