Designer Step-In Pet Harness Scotland Auburn (Size 0) Size 0: 1-3 lbs, neck 10"-11", chest 11"-13" Harness is designed to prevent bruising around the pets trachea area when pulling. The straps adjust to measure the neck and chest girths accordingly to ensure a perfect and comfortable fit. The harnesses are also designed with an easy fasten side-release buckle, which secures your pet into place. The center rings above allow for attachment of a leash for those long and happy walks.