Adjustable from 18 to 28cm, excluding AirTag, you will received 2pcs. [measure your dog's neck circumference before ordering,using a tape measure or string around your dog's neck. (A distance of two fingers between the collar and the dog's neck is recommended for best results, to prevent the collar from strangling the dog's neck too tightly and to prevent the dog from biting the collar)] Comfortable material-Handmade cute dog collar made of soft and lightweight polyester material with a double layer of cotton, light weight, comfortable, breathable and skin-friendly while more durable. Exclusive individual design-Exclusive design patterns don't have to worry about meeting the same model in the market, making your pet the most personalized dog in its circle of friends. This colorful, bright and personalized collar makes your dog look more fashionable when traveling and on daily walks. Quick release adjustable dog collar-Quick release and secure buckle with coated alloy D-ring, easy to put on and take off, we have many sizes of collars to choose from, collar size is easy to adjust, adjustable from 18 to 28cm,suitable for both puppies and adult dogs or growing dogs.