Spring loaded Hinges.
Quality Plastic Reading Glasses +1.0~+3.5 Spring Hinges Classic Black Arms L876
Superb Quality Plastic Reading Glasses Spring Hinge Arms Classic Designed R364
Valued Quality Mens Womens Plastic Reading Glasses Full-Rim Or Semi-Rimless +3.5
Good Quality Big Lens Simple Plain Plastic Reading Glasses Comfort Designed 140
S140 High Quality Big Lens Simple Plain Plastic Reading Glasses/Comfort Designed
Valued High Quality Sport Style Matt Plastic Reading Glasses Comfort Design L152
