CDCR HASH MARKS / YEARS OF SERVICE. 1 Hash Mark = 4 Years of Service SIZE: 2" x 3/8" Sewn on Black Felt NOTE: If you have to add another Hash Mark, you MUST remove and replace with a 1 PIECE Hash Mark. Example: Have 2 hash marks, need 3 hash marks, Remove the 2 hash marks and replace with a 1-piece hash mark that has 3 hash marks. You CAN NOT just add 1 hash mark.