The Wiley X SG-1 features a removable lens system. The prescription lenses reside in a removable gasket, enabling you to have multiple prescription lenses for one frame. You can have a pair of clear lenses, a pair of smoke lenses, a pair of polarized lenses, etc. To purchase additional prescription lenses for this frame, click here.
The SG-1 also converts from a regular frame to a goggle. The temple bars (the arms that go behind your ears) are removable, and the frame comes with a goggle strap that clips in in their place. This means that you can wear the SG-1 as a regular pair of sunglasses or safety glasses, and then during situations when you need the frame to be more secure you can wear it as a goggle. This frame is ideal for military use, motorcycle riding, and extreme sports.