I recommend a headlamp instead of a flashlight, so you can have both hands free. PrincetonTec makes a regulated headlamp with filters called the "Eos Tactical". It has 3 replaceable filters, red, green and yellow.

A "regulated" headlamp means that, with lithium batteries, the light won't gradually dim as the batteries weaken but will burn at almost the same brightness until the very end of the battery life, where the light drops off very quickly. therefore you get more useable light from your batteries with regulated headlamps.

Eric