Reddit mentions of Walk 'n Train Dog Head Halter, Bright Pink, Size 02, Medium

Along the same lines as the no-pull harness (which is fantastic) is the head collar (I like the kind with the safety line that attaches to the collar so not "gentle leader" brand)

Yes it looks like a muzzle, but for a reactive dog they are a great emergency tool, and have really enabled me to move forward in leaps and bounds with my guy.

Basically I would walk Jack on a harness and switch to a headcollar when I saw a dog in the distance (if he saw the dog first I gave jack a few treats before putting the headcolar on so I could get his attention and not associate the headcollar with the oncoming dog) Then hold his head pretty close and deliver treats (so he's basically staring into my eyes as another dog passes by) If the dog was closer I'd give lot's of good boys, have him walk in circles following the treats, alternate with sits, high fives and "this way" or "follow me" and walk farther away.

That way you're sending a clear signal to the owner that you are in training (the muzzle-like appearance of the collar helps keep bozos away too)

And if the offending dog can't control himself and does come all the way up, you are more in control of your dog, and the body language you two display can diffuse some bad situations

• your dog sitting away from the other dog and walking away means don't come up to him
  
• you are also essentially getting your dog to play in the presence of other dogs, creating a positive situation to build some emotional stability on.
  
  
  Then I'd do a bit more training on the walk or at least go 1/4 mi before taking the headcollar off.
  
  And if used it needs some getting used to, put it on the dog and feed them dinner, or do training with no leash attached and lots of treats, make sure it fits right, and whatnot
  
  Not that doing that alone fixed him, but it was good to have "Evasive Maneuver Delta" in the back pocket. Also gave me the confidence to get him out having fun at more places with dogs as bark explosions reduced significantly about 1 week into starting this.