Petzl Bike Adapt 2 Mounting Plate One Size. Specifications for Petzl Bike Adapt 2 Mounting Plate: Manufacturer: Petzl Weight: 43 g Size: One Size Features of Petzl Bike Adapt 2 Mounting Plate For mounting on bicycle handlebars or seat post between 20 and 34 mm in diameter Compatible with TIKKINA TIKKA TIKKA CORE ARIA 1 RGB ARIA 2 RGB ACTIK ACTIK CORE (2022 model and later) and SWIFT RL (2023 model and later reference E095BBxx) headlamps Confirm your headlamp compatibility in the FAQ Package Contents: Petzl Bike Adapt 2 Mounting Plate Petzl E074AA00: Bike Adapt 2 Mounting Plate One Size