Puppy Bumper, Navy Dot, up to 10 inches Dog's collar threads through loops to stay secure Light, comfortable, machine washable Never fear for Fido's safety near a fence again! Measure your dog's neck to ensure correct sizing Up to 10 Neck  Generally for Toy Breeds approximated up to 11 lbs. or skinny neck pups like Italian Greyhounds or Min Pins. 10 to 13 Neck  Mid-range pups from 12 lbs to about 25 lbs. 13 to 16 Generally over 20 lbs.