The Z-LED is an optional taillight that can be added to certain models of Lazer helmet. It mounts inside the Mudcap at the back of the helmet and provides additional visibility on the helmet. It works with replaceable batteries so it can last forever. Note, the Z1 LED Mudcap (PLZ2005660134) or Blade Mudcap (PLZ2167882106) must be used with the corresponding helmet in order to mount this light.