In my opinion the absolute best deal on a great back-up light is the 1000 Lumen Orca Torch sold by board member Danno with Mako Spearguns. I have two of these. One as my back-up light and another mounted on my speargun. This is a 100% genuine Orca Torch light that's simply been rebranded with the Mako logo.... and almost half the cost... It's an absolute no brainer in my opinion....
1000 Lumens Dive Light
The MAKO Spearguns 1000 Dive Light delivers a HUGE 1000 Lumens with 70 degree projection and 8 degree center beam. Rated to a depth of 150 meters.
makospearguns.com