Size Guide: This dog harness has Fully Adjustable Slide Straps at the chest and neck. suits for Extra Large Dog to Medium such as golden retriever. Labrador. German shepherd. Husky. American bully pitbull. etc. Please mesure the chest and neck girth before purchanse (be sure to set aside 2-3cm) S: Chest Girth: 20-25.5"Neck: 17-23.5" M: Chest Girth: 22-30"Neck: 20-27.5" L: Chest Girth: 28-35.50"Neck: 22-31.5" Be Seen & Safe: This led dog Harness built-in High visiblity 5~6 led lights. So our dogs or cats can be seen from a long distance at night. It is easy to be Seen to avoid some potential traffic dangers. Althougt it is out of power when walking. is is also easy to be seen by cars or persons because it also with some high visiblity reflective fabrics. So it is good choice for you to send your dogs a gift. Comfortable & Eco-friendly fabrics ---The led dog harness is made of breathable & comfortable meshing fabric. Also with foam lining so that dogs neck and body are more comfortable. No-Pull & No-Choke: Dog no escape harness has 1 sturdy metal leash D-rings with reinforced stitch for safer dog walks. You could attach the chest ring to control your dog when dog pulling. The back ring for casual walks. jogging. hiking. trekking. etc. The dog harness anti pull has no stress on dog's neck. pressure is evenly distributed to the body to prevent pulling and choking. And the Vertical handle helps you to control and assist your dog. USB Rechargable & Flashing modes: Get it full charged 2 hours. then can last 3hours for steady glow or 8 hours for fast flashing. Note: Due to the light and screen setting difference, the item's color may be slightly different from the pictures. Please allow slight dimension difference due to different manual measurement.