These are electronic ultrasonic units rather than sprays, so there is nothing to refill, no liquid to carry through security and no scent on your skin or clothes. Most charge over USB-C or run on a small built-in cell, and several clip to a bag or belt loop. The effectiveness of ultrasonic repellent technology varies with conditions and species, so treat these as a convenience option alongside your usual precautions. By shipping directly from our manufacturing partners, Blacksheep makes outdoor gear available at up to 80% off standard retail prices. Read less