How to choose the right size harness 1Please kindly measure your pet dogAs neck girth and chest girth before purchasing 2Please allow 05-1 inch error due to the manual measurement 3Here are the Harness Size guide for your reference: XXX-Small --- Neck girth (86-10 inch),chest girth (11-13 inch) XX-Small --- Neck girth (10-12 inch),chest girth (13-17 inch) X-Small --- Neck girth (11-14 inch),chest girth (16-18 inch) Small --- Neck girth (14-18 inch),chest girth (17-21 inch) Medium --- Neck girth (17-25 inch),chest girth (21-29 inch) Large --- Neck girth (21-31 inch),chest girth (25-37 inch) Elastic Safety Seat Belt: 2087 inch - 2913 inch x 098 inch (L x W)A Outstanding features of the Lukovee Dog car Harness Plus connector Strap: 1 Multiple design and shape is our innovative collocation to be great for your traveling with your puppy dog 2 The material we adopted are the tough durable nylon fabric belt and the double mesh fabric vest harness strap, which can be a great protection for your dog Why choose the Lukovee Dog car Harness Plus connector Strap 1The harness strap is designed to be universally compatible with most standard vehicles while securely keeping your pet in place for safety traveling 2This multi-functional harness belt not only can combine pleasure with treatment during the journey, also can be a collocation with the retractable dog leash Package Include 1x Breathable Mesh chest Vest Harness Strap 1x Elastic Safety Seat Belt Warm Tips: 1Please measure your pet before your purchase 2Please take each measurement a bit loosely, so there will be room for your pet to move and breathe