LED Backup With a tried and true design, the 2 Watt and 3 Watt LED lights are constructed from a solid rod of Delrin® for years of reliable use. Delrin makes for a rock-solid light and will not corrode in a salt water environment. The LED backup lights include a simple twist on/off design with a double O-ring seal. The bodies are knurled and grooved to provide a secure grip, even for hands in dry gloves. 2 Watt LED We've specially designed the 2 watt to have the ability to be mounted to a mask strap with two 216 o-rings Powered by two CR-123 lithium cells (included) 3 Watt LED Backup Powered by three c-cells (included) Double O-Ring Seal Burn Time - 600 minutes Lumen Output - 600 Beam Angle - 8° Body Diameter - 1.4" (3.5 cm) Bezel Diameter - 1.75" (44 cm) Overall Length - 8" (20 cm) Depth Rating - 500' (150 m) BATTERIES SHOULD BE INSTALLED WITH POSITIVE POINTED DOWN AND NEGATIVE TOWARDS THE LIGHT HEAD Double O-Ring Seal Burn Time - 360 Minutes Lumen Output - 125 Beam Angle - 13° Body Diameter - 1.2" (3 cm) Bezel Diameter - 1.35 (34 cm) Overall Length - 5" (12.5 cm) Depth Rating - 500' (150 m) BATTERIES MUST BE INSTALLED WITH NEGATIVE FACING DOWN AND POSITIVE TOWARDS THE LIGHT HEAD