SF is right. They are rated for approx 150 hours of wet time for double flashing, approx 200 for single flash. Batteries cannot be replaced due to water proofing and pressure resistance design. I do have some units that the batteries can be replaced in, but they are bigger, bulkier and heavier so I do not market them. Instead, I use them when doing tests and because of the number of LED's and microprocessors they use, I replace batteries before each trip out.
Flashers can be used with LED products as they provide action to the lure.
Our LED lights come in single flashing blue, single flashing green, single flashing 7-color, double flashing green, double flashing white and double flashing UV.
A note on the 7-color unit: This unit cycles through 7 different colors and at two cycle speeds automatically. Due to number of LED's and microprocessors, this light lasts approx 20-25 wet hours.
Water temp can play a part in life of the batteries though we've not had a complaint about them. There is an ongoing debate about freezing batteries to prolong the life and that debate has carried over to enviromental effects of the batteries. Duracell says do not freeze them. Others say you may. Perhaps it comes down to battery design. We've not had any problems.
Water pressure may be an issue if you are fishing at 3000ft or more in depth. Otherwise, you will be OK.
As for which lure or lure color to use, SF or others fishing that area would be your best advice.
Hopefully, this post helped.