Bad bag, not in terms of quality but in usability. First of all, the bag requires a drill to attach one piece of the base, secondly, the cord that releases it is short and needs a workaround (I used a fluorescent shoelace so I can find it and pull it in the dark) and most importantly, the pocket for viewing the phone is completely useless since the bag sits parallel to the tank and thus the phone is looking at the sky and not at you. The only good thing about it is that it is expandable so it can hold many items inside and if one day you have it slightly empty, you can reduce its size and it doesn't move with the speed. It comfortably fits a thermos cup for coffee, along with a sandwich, and an extra bag that contains a phone, glasses case, granola bar, and crackers. I wouldn't buy it again; I would prefer a magnetic one.