Kpop Lightstick (응원봉): 5 Iconic Designs and How Sync Works
A kpop lightstick does 2 jobs: it shows which group you love, and it makes you one pixel in the concert light show. Almost every group with an official fandom releases one. A stadium full of matching lights is the most visible proof a fandom exists, and the agency can control every one of those lights from the stage.