550 mm long, 250 mm wide and 260 mm high. General brand fitness bags have small dimensions of 550mm long, 250mm wide and 260mm high, and large dimensions of 570mm long, 260mm wide and 280mm high. It is suggested that girls buy a small size and boys buy a large size. If many boys don't have small-sized fitness bags, then choose a fitness bag with a length of 550mm, a width of 250mm and a height of 260mm below 160.