Gentle Leader Headcollar 5/8" Nose Loop Black, Medium for Dogs 25-60 lbs. Wont choke...pressure is applied at the back of the neck vs. the front of the throat. Not a muzzle...when fitted properly a dog can open its mouth to eat, drink, pant, fetch, and bark. Can be worn up to 18 hours/day. The 5/8" thick nose loop fits better on dogs with long noses like labs and shepherds.