eBay
I have 2 XXS harness vests , 1 blue and 1 pink
fastens around neck and under the tummy and are adjustable
they are a bit bobbled but still have lots of wear left
Fits a very tiny puppy, up to about 6/7 months . my dogs are a cross between a Chihuahua and Yorkshire  Terrier. they fitted perfect until about 6 months
 the pink has lettering born to be a  princess and blue has cool dude .
will sell separately if needed