There are five categories of lenses:

Cat. 0: None or very light tint. Spectacles for aesthetic, fashion or comfort purposes.
Cat. 1: Light Tint. Spectacles for weak levels of sunlight and provide limited UV protection.
Cat. 2: Medium Tint. Suitable for average levels of sunlight.
Cat. 3: Dark Tint. For use in strong sunlight, including light which is reflected off of water or snow.
Cat. 4: Very Dark Tint. Special-purpose sunglasses for use in exceptional levels of strong sunlight. Not suitable for drivers.

Most lenses used by R.T.CO are Category 3, unless marked otherwise. All R.T.CO lenses offer 100% UV protection (UV 400). R.T.CO does not currently offer prescription lenses services, however this can easily be done at any optician.


Store sunglasses in a dry place, at temperature between -10°c and 35°c. Clean with water & soap as needed. All R.T.CO sunglasses come with a microfibre cleaning cloth for daily maintenance.

R.T.CO sunglasses are made from cellulose acetate which is a natural and renewable material that is light and wear-resistant. Due to the highly malleable nature of acetate, it makes fitting very simple. However, sometimes the glasses can become crooked or bent with time and wear. This can be fixed at any optician or here at R.T.CO store during opening hours.


If you want to have your lenses replaced due to wear (scratches or opaqueness) or if you prefer a different lens color, you can send your sunglasses to us for lens replacement. We offer Green, Brown, or Grey Lenses.
Costs for this service are: 40 € within Germany (incl. shipping) and 50 € International (incl. shipping)

If you have any other concerns, e.g. a lost screw, broken hinges etc.,
please contact us at hello@r-t-co.com