Alfonso Pacheco wrote a review of Norrøna Bitihorn Flex1 Zip-Off Pant - Men's on June 5, 2013
These pants are stretchy and very breathable. They have a back pocket too which is not mentioned. You can also adjust the waist with the straps they have (I normally wear 31, ordered the medium and fits great; I guess the sizing chart is a little off). The fabric is strong and can withstand tress, branches and rocks.