These are one of the only nappies available on the market that actually fit premmies. Our bub was just over 3 pounds, and these nappies fitted perfectly, and would fit slightly smaller babies, at least down to 2.2 pounds (1 kg). We used them until our bub grew into cloth nappies, and for those 2 months we had not a leak or a 'poo explosion'! They have a wetness indicator on the front that prevents unneccesary nappy changes, and the umbilical cutout allows a good space for the cord to be free of interference. Very highly recommended for small babies.