Poor craftsmanship
I been using the (welding) flip up shades for 30 years and was quite disappointed when they arrived. Right off, I noticed the poor quality and the lenses were not aligned with each other (the lens welds were not aligned). Then I went to install them on my glasses and the points where the frame slips over the glasses was not even close, unlike the other two flip lenses I have, they pop right on. So, whoever made these, made the connection points on the flip ups way to far apart, to fit any glasses properly (1/2" to far apart). Consequently, I spent almost two hours bending and trying to find a way to make the flip ups fit. Unfortunately, I had to use zip ties to make it work and now I can't take them off, without a lot of labor to put them back on.