These designer prescription glasses are made to accommodate most prescription lenses.Made of plastic, otherwise known as cellulose acetate, or zyl, the frame can be easily adjusted for a perfect fit with your prescription lenses. Your frame purchase includes free standard shipping charges, and manufacturer packaging. You can add doctor verified prescription lenses, add custom polarized lenses, and many other lens options if you desire them. Like all Sferoflex products, the Sferoflex TF2137F provides the sophisticated and classic look that we all need. Sferoflex TF2137F frames feature a fashionable full frame design, which is the largest component of designer eyeglasses brands collections. A rim all the way around the lenses, provides for maximum stability and durability. See all Sferoflex Sferoflex Eyeglasses Sferoflex Glasses: Sferoflex is the name of the eyeglasses line characterized by a spring temple invented and patented by Sferoflex glasses in 1941. Many years have gone by since Luxottica Group took over Sferoflex (in 1982), yet the Sferoflex glasses are manufactured still today in the very same plant located in Rovereto, Italy, where they were originally born. The very name Sferoflex indicates the main feature of these glasses: the flex temple. A special spring mechanism inside the hinge makes the temples flexible and allows the glasses to adapt to the size of every face without causing any annoying constraints, and thus providing an extremely comfortable fit.