It has a protective plastic outer sleeve and emits 360 degree of illumination that is visible up to 1 nautical Mile (3 miles from air).The PML offer PFD clip attachment,one hand activation,and is maintenance free, Non-toxic,non-flammable and waterproof. Applications:Personnel identification, rescue-at-sea signal, man- Overboard light,evacuation signal. Coast guard approved for waters above 50F. USCG# 161.012/2/1. NSN Approved with a wide range of uses.Color:Green. Duration: 8 hours