Weebo Pets Adjustable Nylon Dog Collar with Hi-Visibility Reflective Thread A collar that's both fashionable and functional! Built to last. Constructed with tough, long-lasting nylon webbing and secures with a durable, heavy plastic buckle Features hi-contrast reflective thread stitched directly into the nylon for extra dusk and night time visibility Easily adjusted to fit your dog's unique physique. Large collars adjust from 14.5" to 21.5" and are a full 1" thick If your dog's collar is fitted properly, you should be able to slide two fingers between it and your dog's neck