In roulette lammers are often used to mark a value of roulette chips being used. They usually place a lammer on top of a color of chip, unually on or near the wheel (depending on the casino and jurisdiction). This reminds the dealer, games supervisors and surveillance on how much the chips are worth when the guest is buying more or cashing in. Usually most casinos won't use lammers to mark someone using chips bought at minimum bet.