It wasn't all that long ago that carrying a dive light of any real power meant you could shed a block or two of lead from your weight belt, but thanks to improved bulb and battery technology, the latest in powerhouse lighting is more compact than ever. Underwater Kinetics' upgrade of the venerable SL4 packs a big punch with just four C cells thanks to new super-bright eLED technology.

Most of my time with the UK SL4 eLED was spent in semi-dark conditions rather than the inky blackness of a midnight dive. Any light looks brilliant against the darkest of backdrops, but the best hold their own in low light conditions as well. Scoping out the underside of a rocky ledge during daylight hours, or peering into the folds of a thick kelp forest, are great ways to get a feel for a light. The SL4 eLED produces 3 to 5 watts and was a solid performer in these types of conditions.

From its earliest days, the SL4 has been a do-it-all light, and I've used the older version for years. It's compact enough to stow in a BC pocket for every dive but bright enough to carry the load on a night dive. With UK's development of eLED technology, the do-it-all mantra continues to ring true. The eLED version is fantastically bright and efficient. It produces a beautifully white, high color-temperature light, and UK has done a nice job of crafting a relatively tight beam pattern that's perfect for spotlighting critters in dark corners. A much larger, softer outer ring of light is also produced, and it's well suited for sneaking up on shy creatures at night that might be easily spooked by a brighter blast.

UK's eLED technology is intense, but it offers a few other benefits as well. The eLED circuitry produces a consistent level of output until the batteries are nearly depleted, about 10 to 12 hours, meaning you get reliable performance during the whole dive. Once the batteries are nearly exhausted, the light output will become somewhat faint, but it will continue for another 12 hours or more. This can be a great asset in an emergency, helping you read gauges or signal for help. A second unique design element of the eLED is that it burns a bit brighter underwater than it does on land. When the light is submerged, the water helps disperse heat and the eLED produces even more light.

Externally, the SL4 is not much changed, and that's a good thing. Solid ABS and polycarbonate plastic construction have allowed my old SL4s to survive years of use and dozens of international flights without harm. A simple switch just under the rubber-sheathed bezel is easy to manipulate but not prone to accidentally turning on when the light is jostled around in a dive bag.

UK SL4 eLED

Impressions New eLED circuitry continues to make the SL4 a true do-it-all design that's brighter and more useful than ever. Features High-intensity white eLED light, consistent light output for duration of batteries, ultra-durable construction, lanyard and batteries included.