This is the Puppia we use on Snickers and it works very well. When Snickers pulls, he does pull hard it he makes that weird dog cough sound, but he did that with reg step in's as well. We LOVE this vest type of harness and Puppia uses a really nice velcro, so Snick's hair does not ever get caught in it. Snick is only 3.5lbs so I had to search for an Xsmall, but I found one and it's perfect, I also have a size Small as well, but it's too big on him.
Amazon.com: Puppia Vest Dog Harness Pink Medium:...
Good Luck
-Snick & Viv