• Extra Small  - 9/16 inches wide and fits necks 9-12 inches
• Small - 9/16 inches wide and fits necks 12-16 inches
• Medium - 1 inch wide and fits necks 14-21 inches
• Large - 1 inch wide and fits necks 18-28 inches

Measuring your dog's neck
We recommend using a soft measuring tape. If you don't have one - use a piece of string, and measure that. Remember - you'll want to get two fingers under the collar when it's on, so take that into account.