I still think some of the step in harnes still chokes that is if you pull hard. That is why we carry the ones that around from the front hind. Sometime like this won't choke
http://www.barkatme.com/shop/item.asp?CatID=&Sku=840
or
http://www.barkatme.com/shop/item.asp?CatID=69&Sku=1174