KONG H2O Bottles come in two sizes. The large bottle holds 25 fluid ounces or 740 ml and the small bottle holds 9.5 ounces or 280 ml. The 25oz/740ml bottle's lid will hold 8 1/2 fluid ounces per serving, although we recommend serving less water, more often. The 9.5oz/280ml bottle's lid holds 3 fluid ounces per serving.