Osprey Syncro 3 Hydration Pack A zippered top slash pocket lined with scratch free, heat embossed fabric proves ideal storage for optics and electronic devices Osprey's LidLock easily and securely carries bicycle helmets The blinker light attachment strap found near the base of the front panel of the pack allows for quick light attachment The main compartment of the Syncro 3 is designed to accept up to a 2.5L Hydraulics reservoir