Rivet pet collarMaterial: PU size Adjust the collar xs 2. 5*32cm 21 27 S 2. 5*37cm 27 33 M 2. 5*42cm 32 38 L 3. 5*51cm 37. 5 47. 5 XL 4*61cm 44 56 NOTE: Manual measurement exisits 0. 5 1 inch (1 3cm) error. Note: before ordering, make sure your dog is suitable for this size (this is very important). Product size as real horizontal measured manually, there may be 1 3cm error, please pay attention to this factor when you order!