Party hard with Flashing Whistles! These light up novelty necklaces make fantastic party favors. They're great for parties, concerts, and any fun night-time event. Each box of 24 whistles comes with 4 assorted colors - clear, purple, blue, and green - and each necklace has an attached black lanyard. Blue, yellow, orange, and red LED lights flash randomly. 3 AG10 batteries are included and replaceable using a small Phillips head screwdriver.