Dogs are rough on gear - there is just no way around it. Rex Specs are design to easily change out the lenses when the light conditions change or the lenses become too worn.
Note: Mirror lenses are the same darkness to look through as the smoke lens but have a mirror coating applied. This coating does scratch. We've made them as durable as possible - but if your dog goes after a squirrel in the rocks or bushes with their mirrored lenses - the lenses will show signs of the hunt! The UV protection is not compromised by scratches - use them until they're completely beat!
Spherical, polycarbonate, UV 400 lens protect against 99-100% UVA/UVB sun rays