The 117A plastic headgear fits all Huntsman helmets. The patented Zahnlok size adjustment system provides a custom and secure fit, allowing adjustments to be made in 1/16" increments, by turning a easy-to-use knob. The teeth area automatically disenagaged during adjustment for less "wear and tear." The durable, CoolMax terrycloth sweatband offers additional comfort and is also washable.