The dog baseball cap Have three sizes available, S---Hat Diameter: 3.35""/8.5cm, head circumference:11.02""/28cm, M--Hat Diameter: 4.53""/11.5cm, head circumference:13.39""/34cm, L---Hat Diameter: 5.51""/14cm, head circumference:16.14""/41cm The pet outdoor sports hats are designed with 2 ear holes which can let your pets show their lovely ears; And the chin strap can be adjusted according to yours pet's size; And also the chin strap can prevent the hats being blown away by wind and falling during the pet's playing Material: Durable canvas ,breathable and comfortable Outdoor Hat,Protect your pet's eyes from sun rays. Let your pet enjoy various outdoor activities in the sunshine. Baseball caps can be applied when you and your dog are exercising, and it looks elegant when you go for a walk,Dress up your pets with this hat. Let you become the coolest guys in the street.