Nose pads that attach to an eyeglass frame by a small nose pad screw. You can tell that a frame has a screw in mount when you look behind (or to the back of the nose pads) and find a small screw box, or area where the base of the nose pad fits into the frame. This area will have a small nose pad screw that runs through the box and the screw hole of the nose pad to create retention and allow the nose pads to pivot. The screw boxes on eyeglass frames may vary from rounded edge to a square looking screw box. Some may even have an open faced back where others(most common) are totally enclosed. The nose pad screw may vary from having a flat head screw to a philips head screw. Both will have a screw diameter of approx. 1mm.