See the full review here: http://www.mountainlifemag.ca/2014/11/trek-fast-light/ 

Trek Fast & Light

The mission of Julbo‘s Trek sunglass is simple: to achieve optimum performance while moving fast in extreme environments by providing highly technical, yet lightweight eyewear. For those committed to the outdoors via mountaineering, climbing, and trail-running, the Trek is the perfect combination of tech principles and performance ergonomics.

Detachable shields block lateral rays from intense glare as well as offer superior ventilation when necessary. Julbo’s Flex Nose design and 360° adjustable temples provide optimum hold. It’s available with either the Cameleon or Zebra lens for optimal visibility and protection against intense sunlight from desert to glacier conditions.

ZEBRA
This photochromic lens, developed for the Speed range, is ideal for mountain biking, trail running, and climbing.

CAMELEON
This photochromic lens, anti-fog and polarizing, developed for the Outdoor range, is designed for use in mountain and desert environments.