Interesting! I must look at the Gentle Leader head collar. I think that's the name of the old harness I have from my lovely old dog, who died last year - but it's a harness that tightened gently on the chest rather than on the head. Very reassuring for a jumpy dog.
Presumably I'd get the small size for a puppy? He's doing pretty well, but LIFE IS TOO EXCITING!!! at the start of a walk. Perhaps I should tire him out with vigorous Fetch before walk time.