Paul Bakerwrote a review of Mammut Boulder Chalk Bag on July 1, 2016
Familiarity: I've used it several times
I use this little bag all the time bouldering either at the gym or in my backyard. It carries more than enough chalk and is deep enough to completely fit my hands in it. The closure is a bit iffy, but as long as you're not sloppy with it, it's absolutely secure enough to keep chalk from spilling out. I have another chalk bag that rolls down completely 3-4x and is less secure than this one.