I'm not sure if I know which ones you're talking about, but the ones in the US are usually these:

The noose is usually placed loosely on the dog's neck, but some people place the noose snugly on the dog's neck, right behind the ears. There are also different types of nooses and different materials they're made of. Many people choose to use a thicker material for puppies. I'm not sure how other people use theirs, but I know my breeder doesn't leave the noose tight around her dogs' necks. It's always loose enough to allow the dog to sit, stand, and lie down. Plus, Pekes are a loose lead breed, so I don't see the point of a tight noose.