MACK Photochromatic Glasses
So, these are really cool and they really work.
"The off road cyclist on our team uses them and rates them highly."
Photochromatic lens (non-polarised) transitions from clear to dark in around 8 seconds, and reverses to clear in around 35 second
A PC deep crystal black and red wrap around 8 base curve frame to ensure a snug fit onto the face for close fitting eye safety and comfort. Comfort is enhanced by smooth edged side arms and frames which are coated in a high gloss extra thick coating and the nose bridge is a PVC free “in frame design” for hygiene and long lasting stress free wear-ability. Standards: AS/NZS 1337.1 Medium Impact