SIZE CHOOSING - Do not choose harness size based on your pet's breed size and age. Please refer size chart in the product images. SPECIAL USAGE INSTRUCTION - Adjust the buckle and push it inside the harness to extend the size according to your need. SAFETY DESIGN - Reflective straps ensure your dog's safety while out for a walk.With a sturdy handle on the back,you can control your dog directly by your hand. Two Leash Attachment Points - Zinc alloy D-ring on the dog's back, they are very durable and distracted the pull of the leash, let the dog vest force of the dog be more uniform and not inclined to one side, keep your puppy's safely. Size Note - Please measure your pet's chest size, according to your measurement results, select the correct size and purchase. Please choose the size best to set aside the width of 0.7-1.1 inches.