These 30mm wide Hi-Viz yellow reflective bands are great for daytime and nighttime visibility.Quick and simple to use. They have a recoil sprung metal strip inside the plastic outer. To fit the strap, you simply Oslap the uncoiled band onto your arm or leg and the metal recoils the strap around your limb.  Caution: If the plastic outer becomes damaged, always discard the item, as the thin internal spring metal strip can be dangerously sharp when unprotected.