My baby is 6 weeks old. 13lbs, and 59 cm long. He still slips down too much for me to use this as water keeps getting in his ears. Product says ideal for up to 6 months, but weight limit is 20lbs. Every baby is different in height and weight gain. My son will probably hit 20lbs by 4 months. They should really update or remove their "ideal age" range.