I bought the 10 foot version for double doors opening in the middle. Very straight forward installation, I didnt read the instructions (did look at the pictures) and it came out perfectly. Heavy duty steel hardware except the wheels which are POM Polyoxymethylene (POM), also known as acetal,[2] polyacetal, and polyformaldehyde, an engineering thermoplastic used in precision parts requiring high stiffness, low friction, and excellent dimensional stability. translation: a high quality smoothly rolSee full review