really depends on what your requirements are for a tech backup light are. Do you need a backup light that runs of alkaline batteries or are rechargeable batteries ok? (rechargeable seem to be much more common now a days and less expensive). I have a couple of the DGX600s, one push button and one twist. They use 18650 batteries but I have done burn tests on them using 2xCR123A. With the 18650s they last about an hour (little over) and with the CR123As they burn 2:45 hours, allthough with slightly less light output. I prefer the button DGX600 with a soft goodman handle for rec diving, I find the 600 lumens output and 1 hour battery life to be more than sufficient and the size (and price) are very good. That said there are agencies that won't let you use either a push button or a rechargeable battery in a tech backup light.