Dual-purpose bell that also discreetly houses an Apple Airtag (sold separately)Apple Airtag is stored inside the base and is nearly impossible to spot when fully assembledDurable fiber-reinforced plastic base with aluminum bell housingLoud and clear 85db bell alerts pedestrian and other riders to your positionBell w/AirTag Holder31.8mmBlackUPC/EAN/GTIN: 8720865500065