SMALL: 3 x 4 x 1 inches, Holds 3 gel packets, keys, or cell phone * MEDIUM: 3 x 5 x 1 inches, Holds 2-3 energy bars, 5 gel packets, cell phone, or iPod * LARGE: 4 x 5 x 1 inches, Hold 4-5 energy bars, 8 gel packets, cell phone, iPod, or compact camera