Standard sizes:
Toy- Fits necks 5-8" (ONLY available in 3/8" WIDTH)
X-small- fits necks 7"-10"
Small- fits necks 9"-14"
Medium- fits necks 13"-21"
Large- fits necks 15"-25"
X-Large-fits neck 17"-28"
Collars are available in 3/8, 1/2,5/8,3/4,1, or 1.5 in.widths.