I love this bag. It fits up under my seat really well. I have an aero seat post and Velcro straps that go around the post on most other brands tend to stick out. This baby is all safe and sound out of the way and has enough room to carry two tubes, a tire boot (a must if you ride solo out beyond civilization and cell service), two CO2's and the related nozzle, tire levers and a small patch kit. I carry a multi tool in my jersey pocket. I have not experienced the falling off that others have talked about, and I have used this bag on the 2017 Belgian Waffle Ride course (40 miles of dirt and single track/rock gardens/washboard to go with 100 miles of road). Yes, like any bag with a metal zipper, you will eventually experience reduced performance riding with it in the rain, dirt and wet conditions. Nobody expects a bag to last forever, do they? The last bag I had before this one (another quality brand) was retired due to a zipper that finally gave up the ghost after a marathon four days of riding in the rain and dirt, and that was after a good solid year of riding.