Products webpage:
https://www.cheerycurtains.com/chr41-ceiling-wall-mounted-thick-aluminum-alloy-double-curtain-tracks.html 
Those who work in versions of V-Ray below 3.1, be careful. In the materials of the BRDF section, Microfaset GTR is installed; if the version is older than 3.1, then the BRDF field will be empty. Choose Blinn, Phong or Ward - whichever is more convenient for you...