double eyeglass spring hinges

Here are collection of double spring hinges, TSH-52-A,TSH-53,TSH-60,TSH-76 etc,all of them have double springs inside the hinges box which makes them to be the most durable eyeglass hinges. And most of  them are easily installed by torx screws directly,such as TSH-52-A,TSH-53 and TSH-60 etc.