This bow is designed to attach to any size collar or harness using 2 sets of velcro hidden on the back of the bow Sizing: -extra small: 3" wide, 2" high -small: 4" wide, 2 1/2" high -medium: 5" wide, 3" high -large: 6" wide, 3 1/2" high -extra large: 7" wide, 4" high Care Instructions: Machine wash in warm, dry on medium heat, iron as needed