Purchased from VS Eyeware (via Amazon). The yellow lens are of good quality, however, in my instance, the lens are attached with insufficient clearance between the two lense - the lens are attached too close to the bridge of the glasses. I have another pair of generic clip-ons (polarized for day use)that I purchased at a local discount store that fits perfectly for my lower profile glasses.  The size of the yellow lenses (51mm X 29mm) would fit perfectly over my glasses if each lense could be moved out about 4mm from center - I just wish there was a way for me to re-position the lense, but, I guess for $12.95 I can live with a 4mm gap on the outside of each lense that is not covered by this clip-on. I am still "evaluating" the usefullness of these "yellow" lense for night time driving (hoping this will help a little degradation with depth perception at night(comes with aging (sigh!)eye sight)) - initial impression is good so far.