This is the second Cocoons product I've bought. I love the first that I purchased about a year ago: Aviator style, tortoiseshell frames. Before purchasing both products, I checked the Cocoons site and carefully followed the sizing instructions, but this MX Rectangular frame fits a bit too tightly over my regular glasses frames. Furthermore, the plain black MX frames look and feel very cheap. I do not know whether this is due to a decline in quality or whether their black frames have always differed from the tortoiseshell. The next time I'm in the market for another pair of fit-overs, I won't buy black Cocoons.