To select the most accurate size collar for your pet, measure the center of their neck with a cloth tape measure, a few inches down from their head. Pull the cloth tape measure snug, but not tight. If you don't have a cloth tape measure, you can use a piece of string and measure it with a rigid ruler afterwards. Make sure there's enough room for about two fingers between the collar and your pet's neck for comfort.
| Size || Neck Size || Collar Width |
| X-Small || 9 to 13 inches || 2/5-inch |
| Small || 12.2 to 17 inches || 3/5-inch |
| Medium || 14.5 to 20.8 inches || 4/5-inch |
| Large || 17.7 to 27.5 inches || 1-inch |