Interchangeable lenses have always been an issue with notoriously weak screws or awkward lens mechanisms. So we created a whole new lens-click system that erase these problems. All of our Eclipse series sunglasses comes with a small GPS bluetooth tracker. It rests safely inside a pocket of the sunglass case that comes along and runs on a battery that last about 2 years before it needs changing. We have made our product foldable two ways to fit any size pockets. Shirt pocket, trouser, purse or wallet… With our collapsable design, our glasses fold to only 5cm x 2cm.