Petzl Bike Adapt One Size. Specifications for Petzl Bike Adapt: Manufacturer: Petzl Weight: 40 g Features of Petzl Bike Adapt For mounting on a bicycle handlebar or seat post between 22 and 30 mm in diameter Compatible with TIKKINA TIKKA BINDI ACTIK ACTIK CORE headlamps (models made before 2022) Package Contents: Petzl Bike Adapt Petzl E000AA00: Bike Adapt One Size