Keisuke Omi wrote a review of Mammut Zephir Chalk Bag on May 23, 2011
The front and back panel is fine plastic mesh which helps to give the bag a shape. The material has a strong shine to it which gives it a scifi look.
The black inner bag is attached to the mesh/cloth outer bag at the opening and at the very bottom only. Because the middle section of the inner bag isn't attached to anything, I've found that it tangles with my hand when I reach inside for the chalk ball.
The bag is quite small. The Metolius refillable chalk sock fits exactly inside - practically no room left for my hand to grab the chalk ball. Maybe it'll be fine with a smaller chalk ball and smaller hands.
The draw string that closes the bag is made of an elastic material. This is stupid. You have to pull on the string till it's fully stretched before it starts to sinch the bag. Why?