We designed the Gravity model to be functional multi-focus reading glasses for Mechanics. There are a few "car guys" at Sightline and we were tired of having our readers fall off while we were in odd positions working on our cars. The ratchet action temple holds the glasses in place no matter your head position.
These reading glasses are also remarkably strong. Fear not if you drop them, or toss them on your work bench. They are made of TR-90:
TR90 was produced through Swiss technology as a thermoplastic material that is incredibly durable, flexible, and lightweight. Glasses made with TR90 are extremely comfortable because they have a flexible quality. Since they are flexible, they can bend under pressure and contour your face comfortably. This flexibility also makes TR90 glasses resilient to damage. Because the material is pliable, they are far less likely to break or bend from impact. If you’re guilty of constantly dropping your glasses, fear not! TR90 frames can prevail! Finally, and most remarkable of all, TR90 glasses are supremely lightweight! Even the boldest, biggest styles don’t feel bulky when made with TR90. The thermoplastic material has a barely-there feel that you truly have to wear to believe.
SightLine Multifocal Gravity is a modern take on traditional cable temples like these.