I bought it at an estate sale as a Police helmet. On line shows them as Police helmet (200+ ) It has no name tag , no size. They sell as small , medium , large. I would guess it's medium, measures 7 1/4-7 5/8 across. Looks like it had little or no use, see photos. Thought it would be a neat " Trog" helmet $60 plus shipping, send a zip in private message-Reasonable offer SOLD USPMO or PayPal , buyer handles fees Thanks Roy