The SENSE-ible Dog Harness is an easy to use no-pull dog harness. The front-leash attachment design gently stops dogs from pulling, without causing stress or strain on your dog's neck. Free Instruction Booklet Easy to use right away Quality hardware and construction Nylon curved side-release buckle and belt loops Nickel-plated metal slide adjuster Sizing For the SENSE-ible Harness Using a flexible measuring tape (or leash), measure from just behind the front legs all the way around your dog, similar to a chest or belt measurement on a human. This is your dog's girth measurement. X-Small: 3/8 Inch Webbing (16.5-20.5" girth) Small: 5/8 Inch Webbing (20-24.5" girth) Medium: 3/4 Inch Webbing (24-28" girth) Med/Large: 3/4 Inch Webbing (26-32" girth) Medium/Large: 1 Inch Webbing (27-32.5" girth) Large: 3/4 Inch Webbing (32-40" girth Large: 1 Inch Webbing (32-40" girth) X-Large: 1 Inch Webbing (39-50" girth)