A disruptive force is sweeping through the world of flashlights. You may not think that flashlights are all that interesting, but hear me out: this is force that will not stop at your utility drawer. Within a few years, when all the world’s flashlights have succumbed, the disruptive force will seek new markets. First retail display lights, then office lights, and finally lights in your home will be systematically removed and replaced with something better.

The light-emitting diode (LED) illumination revolution is underway. Cities around the world are replacing incandescent traffic lights with arrays of LEDs, solid-state electronic lights that require less than 10 percent the power of an incandescent bulb to generate the same apparent illumination, and last up to 20 years between replacements.

You’ll find the first consumer LEDs in applications where LED lamps’ advantages-low weight, long-life, and durability-outweigh their higher initial cost. I bought my first LED lamp in a bicycle shop, and you’ll see more in a camping store. There, I found two cute flashlights from Princeton Tec (www.princetontec.com). One, the Attitude, features three ultra-bright white LEDs and claims 150 hours of “burn time” before its batteries must be recharged. The other, the Impact II, has a single LED and 75 hours of burn time. Each measures five inches long, weighs about 80 grams with its four AAA batteries, and fits nicely in my hand. Each will apparently go underwater down to 500 feet. The key difference is that the Attitude has a wider, more diffuse beam, while the Impact II has plastic lens that shapes the light into a beam that travels more than 50 meters (a distance comparable to good incandescent flashlights, but far greater than most LEDs). Another difference is that the Impact has a plastic clip molded into the body, which makes it fit nicely in your pocket, while the Attitude doesn’t. Given the choice, though, I’d still take the Attitude-I like the wider beam and the longer battery life. Expect to pay around $20 for the Attitude and $30 for the Impact.

Of course, not every LED lamp is a winner. Consider the Infinity LED task light from CMG Equipment (www.cmgequipment.com). The Infinity is much smaller than the Impact, has a single LED, runs on a single AA battery, and is advertised waterproof only to 10 feet. CMG claims 41 hours burn time for the standard model; if you want a flashlight with roughly twice the brightness and half the time, CMG offers the Infinity Ultra. In my tests, I found the Infinity disappointing: it was so small that it didn’t fit neatly in my hand, and the lack of a lens meant that the beam really didn’t focus well. Sure, it’s a great tiny light, but at $20 for the Infinity and $25 for the Ultra, it doesn’t really seem worth the money.

Petzl (www.petzl.com), a reputable maker of climbing gear, offers a variety of LED headlamps. Even if you aren’t a climber, you still might find a headlamp useful. By attaching the light to your head, you free up your hands, which makes these lights handy in dark attics, under a car, or even in bed when you want to read at night without bothering your sleeping partner. Petzl’s Tikka ($29) has a big elastic headband, while its Zipka ($33) has a retractable strap that pulls into the lamp unit. Both are powered by three AAA batteries and claim 150 hours of burn time. Black Diamond offers a similar head lamp, but it features just two LEDs, compared with Petzl’s three.

A note about burn-times: Like regular flashlights, an LED light will get dimmer as the batteries weaken. The folks at Petzl, for instance, say that their lights have a 10-meter range with a set of new batteries, but that range goes down to five meters after 12 hours and two meters after 150 hours.

All of the devices mentioned so far use one or more white-light LEDs. But one of the neat things that you can do with LEDs is combine red, blue, and green LEDs to create any color of the rainbow. That’s what a Boston, MA company called Color Kinetics (www.colorkinetics.com) does. The company holds a patent on a method to tune the color of LEDs by varying the duration of electrical pulses to the lights, a technique called pulse-width modulation. It has applied this idea to create a range of products for what’s called “architectural lighting”-that is, using color to set a mood.

I recently tried some Color Kinetics lights-the Color Blast 16-for a few weeks in my house. At the high end of the company’s product line, Color Blast lights cost hundreds of dollars and require special wiring and a separate controller. But like other Color Kinetics lights, the Color Blast combines separate red, blue, and green lights to make white. This should let you dial any shade of white you want, but my wife and I found that the “white” was very cool-not what you would want for home or work illumination. Worse, though, were the shadows: around the fringes you could see little hints of cyan, magenta, and yellow-since it was in the fringes of a shadow where an individual red, blue, or green LED might be blocked.

Color Kinetics is working to overcome this problem by combining a series of white-light LEDs with a few amber LEDs thrown into the mix. The white-LEDs eliminate the multi-colored shadow problem, and the amber lets you tune the color temperature from fire-light to tungsten to a bright summer day. George Mueller, Color Kinetics’ CEO and Co-Founder, showed off this unit at a recent talk, and it was pretty slick. Sadly, it will still be a few years before most of us can afford such technology. For now, Color Kinetics offers a more affordable product line, “Sauce,” that includes wands, night lights, and bulb replacements starting at $15.

So what does all this mean? Color Kinetics’ Mueller predicts that LED headlights and interior lights should start showing up in cars in a year or two-probably in Europe first, since LEDs will allow automakers to use less copper (since the lights require less power), which means lower costs and slightly better gas efficiency.

In the U.S., we’ll probably see LED lights infiltrate offices in five to 10 years, around the time they will have completely conquered the flashlight market. LEDs have huge advantages compared with incandescent bulbs: they use dramatically less power, produce negligible heat, and have a 20-year lifetime. As more LED products come to market, we’ll see them sweep alternatives aside.