Fairtex Full Face Pro Sparring it

Pro Sparring Headguard. Constructed with the highest quality of odorless Micro Fiber. Available in Sizes: Medium, Large or X-Large

Provides maximum safety with a non-deformable iron nose bar, extra padding and wind-shield on the ear

Cow leather lining for gentle feel and easy to clean. Adjustable lace-up on top to fit different heads

Metal Plate Protects Nose and Mouth. Strengthened Seams for a Long-Lasting Quality

Protecting Most Sensitive Areas of a Head: Temples, Chin, Cheek

Triple Density Contoured Foam for Ultimate Shock Absorption

If your head's circumference  is about 54 cm. You should probably fit M size.
If your head's circumference  is about 56 cm. You should probably fit L size.
If your head's perimeter is about 58 cm. You should probably fit XL size.