Size Reference (approx) (1cm = 0.39in): S: Head length is 6.5cm, head to body height is 6.8cm. The elastic band is 156cm long and 1.5mm in diameter. The length of the nylon rope is 46cm, the width is 1cm, the total length of the rope is 120cm; the weight is 59g; parrot weight reference: 110-190g. M: Head length is 7.5cm, head to body height is 8cm. The elastic band is 137cm long and 2.5mm in diameter. The length of the nylon rope is 52cm, the width is 1.1cm, the total length of the rope is 120cm; the weight is 59g; parrot weight reference: 190-420g. L: Head length is 9cm, head to body height is 10cm. The elastic rubber band is 199cm long and the diameter is 2.5mm. The length of the nylon rope is 62cm, the width is 1.1cm, the total length of the rope is 120cm; the weight is 60g; parrot weight reference: 425-600g. One-piece design: no buckle or clip, only one slider to adjust the harness. Automatic Elastic Pull Rope Adjustment: When the bird moves or flies, it automatically adjusts from the chest to the back; the effective pull rope design helps reduce pressure points on the bird. This parrot leash is ideal for birds that enjoy outdoor activities. High Quality Material: The pull cable is made of durable nylon webbing that is flexible and resistant to biting. Easy to Train: With a little patience and positive reinforcement, most birds can be trained to wear this harness. Enhances outdoor experiences and adds fun to daily life.