Daily Digit is the story behind the numbers that make our world work. Today we’re looking at a decades-long arrangement to transfer surplus equipment from the Department of Defense to local police departments. You’ve likely read stories of small-town cops curiously coming into possession of “controlled items,” like bomb-resistant armored vehicles or night-vision goggles. However, the bulk of transfers are much more mundane “uncontrolled items,” such as socks, toilet paper or office supplies. Since 1990, the total value of both controlled and uncontrolled items has come to about $6 billion. While police use of military equipment has come under public scrutiny in recent years — particularly during the 2014 protests against police brutality in Ferguson, Mo. — the program remains active today.