WWI, CALIFORNIA, HIGH SCHOOL CADET, OCTAGONAL COLLAR DISK, HALLMARKED AMCRAFT Circa 1908-1919, Type I Collar Disk Octagonal Collar Disk, Hallmarked ?AMCRAFT, ATTLEBORO MASS? Type 1 Collar Discs were issued from 1910 until 1926. They were primarily issued in a bronze finish and used a screw nut to attach to the uniform. The left collar disc could contain the Regiment number and Company Letter, or number/letter combinations for special assignments. The left disc could also include the regiment number and company letter. To simplify disc production as mobilization for WW1 progressed, the Regiment number was moved to the right disc with the Company letter on the left disc. As mobilization continued and the number of units increased, both letter and number were dropped. Six background patterns have been identified but are considered manufacture variations. Army Regulations issued on October 14, 1921 stated that collar disks were to be bronze on service uniforms and gilt on white uniforms. On November 25, 1924 the bronze disks were dropped.