Dimension of challenge coins: 1.57 inches in Diameter and 0.12 inches Thick. USN&USMC challenge coin is made of Zinc alloy plated ancient bronze. Flag background with rating badge of the US Navy Hospital Corpsman (HM). Perfect gift for US navy corpsman, military veteran and coin collectors. To commemorate the Doc of the US Navy&Marine Corps, it is very suitable for the great corpsman in the USN&USMC. To commemorate the Doc of the US Navy&Marine Corps, it is very suitable for the great corpsman in the USN&USMC.