41 cubic inches 6.25 L x 2 W x 3.25 H. A famed shop in North Dakota with account 007 told our best rep We sell the living % out of this bag he said pointing to an inferior, but novel concept. Cant you guys do better Sure we can. Designed originally for triathletes and ours still works great for that use, our Top Tube Bag is a great add on to keep your must haves phone, wallet, keys within reach. The clear top allows you to see whats in there while keeping it all dry. Plenty of room for race tools, food, or camera, phone, etc.