Multi-functional QR code Qr Code dog collars come with QR code tags. The QR code can record detailed dog information such as the dog's name, personality, likes and dislikes. The QR code can also passively send the owner the address where the dog is and make calls if the dog gets lost, without the need for batteries or other software. LED dog collar light The dog collar LED light comes in 4 colors (red, blue, green, pink), which is colorful and can track your puppy in the dark, ensuring that your dog is safe and sound at night. Easy to use Qr code dog collars can be easily adjusted for tightness, one-click wear and quick release. Qr code is easy to use, does not require software, does not require batteries, activate QR code pet tag can be used. See the picture on the product description page for details. Custom dog collar Scan the QR code to activate the dog tag and register your personalized dog ID tag, which can be modified at any time. When your address, phone number, age or size of your pet changes, you can always ID the content Quality materials Our dog collars are made of highly durable, wear-resistant polyester fibre webbing and stainless steel metal fittings. Double stitching and strong clasp, easy to slip on and off. Adjustable dog collar Adjustable sized dog collars for dogs of different ages and sizes. S-code length for neck circumference 7.5-9.8 inches, width 0.75 inches; M-size length for neck circumference 13-20 inches, width 0.75 inches; L-size length for neck circumference 15.7-24 inches, 1 inch wide.