This bag is great, and the build quality is sturdy and firm. Zippers feel strong and wear-resistant after several rides. However, the supplied straps and drawstring fail to secure it to the frame in a way where it can't slightly rotate or drift off-center. It stays connected to the bike and on the frame adequately, but doesn't feel secure, especially if located underneath the seat (it flopped to the side and came into contact with my legs while pedaling on multiple occasions). This problem was easily remedied with the use of 5 or so zip ties, but I have to be honest that the bag's first impression was a little disappointing.