'''Service Studs''' are metallic studs attached to the skull of a [[Space Marine]], which visibly protrude through the skin of the forehead. The awards signify the number of the Marine's years in service to the [[Chapter]]. Different designs and shapes of studs denote different lengths of service.{{Fn|1}} A stud will represent either 10, 50 or 100 years service, depending on its style and the material it is made from.{{Fn|2}}