24+Hours:Each bottle coaster comes with 2 x CR2020 batteries (included and installed),working for 24+hours,and can be used in bars,home bars,wedding centers,various parties,glass,booze shelf,vase,bottles and night disc golf. Ultra-thin Design: The light up drink coasters are made of laminated foam core board with only 0.118inch adhesive layer. The disc is flat,light and stable,and never affect the normal use of the container. 3 Flashing Modes: The light coasters for drinks have 4 super bright Led lights and 3 flashing modes,fast flash,slow flash,and steady mode. Easy to Operate:Just stick these light up coasters on any normal bottle or drinking glass,and click the button to turn on.