You don't need one - but it's great to have as it helps bring out the colours of the corals and marine life even on shallow daydives. There are always cracks, crevices and swim-throughs to peek into while diving. Not to mention wreck penetration dives, cenotes, cave and cavern diving. The Moray DCT makes a great secondary/ back up dive light with a handy signalling device to get your buddy’s attention. It’s a massive win-win.