Blueberry Pet 5 Colors Soft & Comfortable 3M Reflective Strips Nylon Neoprene Padded Training Dog Harness Chest Girth 24.5-29.5", Chest Width 19", Webbing Width 1", M/L; The chest strap is not adjustable. For a safe and fit purchase, be sure to check the neck and chest; A properly fitting collar and harness won't leave any room for your dog to chew. The harness does not stretch itself. NEVER leave your dog unattended with a harness on. To keep the style and high quality, our designer delicately embedded part of the neoprene harness with 3M reflective materials. The neoprene layer is added to give maximum comfort for your furry friends. All pictures are taken with our production samples from a size 3/4"(wide) * 20.5-25.5"(chest).