The Speedcraft RX Insert frame adapter was developed to insert prescription lenses into the S3. It fits seamlessly into the spectacle design. Clip-on frame adapter made of nylon to accommodate lenses with individual prescription (lenses not included). TPE bumpers reduce scratching of sunglasses lenses and rattling during activities. Matt, translucent finish to suppress glare and light refraction. Seamless integration into the existing nose bridge. Sunglasses for easy installation. Geometrically optimised fit with frame for a wide field of vision. Suitable for +4.00 / 6.75 to 3.00 cylinders: The lenses must be fitted with polycarbonate (1.53) or high index 1.67 and adjusted by an authorised optician in accordance with your spectacle prescription. The lenses must be fitted by an authorised optician in accordance with your spectacle prescription and the pupillary distance (the distance between the pupils) must be greater than 29 / 29. Supplied with nose bridge, nose pads and height adjustment adapter. Fit: S3, Speedcraft (except XS and SL).