FRAMINGHAM, MASS. (NEWS10) — On the 100th anniversary of the State Police Patrol, the uniformed patrol division of the Massachusetts State Police has a red sticker on the back window of their department cruisers. What does the sticker mean?

The red sticker replicates the first patch worn by patrolman. Police say the patch was first known as the “red acorn patch” and was worn from 1921 to 1926 on a green coat over a white shirt and red tie.

An article published in The North Adams Transcript in 1925 said, “State Troopers Wear Bright Red Shields. Every member of the state constabulary, which has a sub-station in Cheshire, is now wearing a bright red shield on his right shoulder bearing the title, ‘State Police,’ in white letters.  The shield is somewhat similar to the divisional insignia worn on the shoulders of World war soldiers, and is designed to distinguish the troopers from city and town motorcycle officers whose uniforms are sometimes similar.”

Massachusetts State Police say this is how they are celebrating their roots. The red stickers will be on the cars through the end of the year.