This was my second attempt at the pencil clip, seeing as the first attempts were failures. The way this one works it based on how the middle grip is off-set from the two outside ones. The way this workz is that the bottom part of the middle grip presses the pencil into the top part of the other two grips. This ensures a very snug, secure fit, keeping the pencil pressed inside of the clip. The clip that attaches to the glasses was designed for Pomy Eyewear brand glasses, but should fit most thick-framed shades. -Far West