The size of this bag is 28x20x5cms. The base width is 8cms. It got six compartments. The back compartment measures 24cms x 14cms. The internal zip is 17 x 14cms. The main zip is 25cms x 19.5cms. The under flap zip compartment measures 19x15cms. The magnet pocket is 25 x 11cms. Our lining is waterproof. The width of the strap is 2.5cms , and the length is 132cms fully adjustable.