Because they are are made from Dupont rubber, there are no screws and the lenses are impact and scratch resistant these are almost (but not completely) kidproof. The decentered polycarbonate lenses provide 100% UVA/B/C sun protection. These glasses have category 3 lenses. The category 3 EU classification means they are recommended for use in bright light in mountainsdeserts and at sea The frames are nickel free and the hinges are stainless steel so they are hypoallergenic Lens base 629gCompatible with prescription lenses