I recently saw a set of Rays Dura-Nuts going for an unbelievable price at a certain accessory shop. Quite frankly, it is quite difficult to tell them apart at a glance as the most obvious difference would be the anodised/hard coated colour on the inside of the threading.
Nevertheless, I did some research online and found this on the Rays website. Perhaps, it is advisable to do a self check prior to purchase.
Have a read below for the official Rays Co.Ltd announcement. Drive and tune safe!