Biodiversity_guy:
So what do you recommend for a daytime auxillary (looking under ledges and into crevacies (sp) light?
I found my halogen SL4 by Underwater Kinetics to be quite adequate for daytime diving, due to the tight beam. The dive masters had the Ikelight 6 AA cell lights (PCm or PCa, I forget which one has 6 and which has 4) which was considerablly brighter, but the trade off is battery life. I suppose the UK SL6 is as bright, but it is a bit big to fit in a pocket... it's as long as 3 "C" batteries, plus the reflector.
My 10 watt HID Light Canon is quite bright, when it's not flooded. Their service has been very good, but I'd prefer not to
need their service department.
So if you want low upfront cost, compact size, and replace batteries every few dives, I suggest the Ikelight.
If you want a bright light that may last more than 5 hours on one set of batteries, I suggest the SL4 or SL6 depending on how long a light you'd accept. (The SL4 should be about 8", SL6 closer to 10".)
The 10 watt HID Light Canon is a powerful light, but there seem to be good reasons why people pay 4 times as much money to buy a 10 watt HID cannister light. I bought my LC for around $170., so it still seems like a good value. When you light up a 10 watt HID (day or night) it makes a spot you can see.
I think my next light is going to end up being a do-it-yourself cannister light using a 50 watt halogen bulb. If it works out, it will be a light worthy of notice.