This collar from SOUF studio is made from durable, waterproof, and easy-to-clean PVC. It is seamlessly adjustable and features a fast snap-on/snap-off buckle. Don't forget to choose the correct size collar for your pet. If two collar sizes are close to what you need, we recommend opting for the larger one. If you're having trouble determining the right size, feel free to contact us for assistance. How to Measure Your Dog's Collar Size: Use a Soft Measuring Tape: Gently wrap a soft measuring tape around the base of your dog’s neck, where the collar would naturally sit. Make sure it’s snug but not tight. Leave Room for Comfort: Add 1-2 fingers' width between the tape and your dog’s neck to ensure the collar isn’t too tight. This provides a comfortable fit and enough room for movement. Check the Fit: The collar should sit securely, but not so loose that it can slip over your dog’s head. Refer to the collar sizes below and compare your measurement to find the correct size.By following these steps, you’ll ensure your dog’s collar fits properly for comfort and safety. Collar Sizes:S: Adjustable from 20 cm to 27 cmM: Adjustable from 25 cm to 37 cmL: Adjustable from 30 cm to 47 cm Measurement: Width: 1.8 cmThickness: 3 mm Materials: PVC-coated nylon webbing Polycarbonate-coated metal D-ring Color-coated rivets *Leash and poop bag holder not included. *Colors of the product may vary slightly from the pictures.