I recommend
Fits well, doesn’t fall off when worn. My female dog is about 4kg, a Yorkie. My daughter forgot to take the nappy off when she took her outside. It stayed on her bum for a few hours until I got home. Everything in the house stayed dry, but the little dog went straight into the bath because she was wet under the nappy. So, as a first aid solution, it’s great, but I wouldn’t recommend leaving a wet nappy on your dog for too long, as it doesn’t protect them from urine and moisture. My dog can’t clean herself, so during her heat it’s perfect, because the nappy stays in place and there are no accidents.