【Refer to our size chart】: Back length 30cm, Chest circumference 54-64cm, Life jacket weight about 0.174kg (Medium). Back length 40cm, Chest circumference 62-74cm, Life jacket weight about 0.2kg (Large). Back length 45cm, Chest circumference 72-81cm, Life jacket weight about 0.46kg (X-Large). Back length 50cm, Chest circumference 82-92cm, Life jacket weight about 0.32kg (XX-Large) 【Easy to put on and take off】: The dog life jacket has Velcro on the waist and neck, and there are buckles in both places. The buckle is adjustable, so you can easily help your dog put on the life jacket. After putting it on, you can tighten or loosen it according to the dog's needs. 【Unique design】: The cute shark-shaped design, with vivid shark fins and other details, increases the fun of swimming and allows you to clearly see where the dog is when swimming. In addition, our safe floating foam can help your dog swim without causing great fatigue. The top of the pet safety vest is equipped with a handle,