All of those mobile phones... mean a growing market for headsets. Bloomberg Boot Camp, a report on today's technology. In more and more places... .hands free units for cell phones are required by law when you're driving. And so the market for headsets has been growing. At Plantronics... which started out making headsets for office phones decades ago... sales jumped forty percent last year. Chief executive Ken Kannappan says new devices are aimed at improving sound quality in difficult environments...

"A lot of times there's a lot of loud sounds around you and it makes it hard for people to understand you and it makes it hard for you to be heard. And the DSP technology that we've created and put into this product really removes those sounds. You could be next to a car that's honking a horn and people will still be able to understand you and you'll be able to hear and understand them. So we think this is a major breakthrough."

The latest is the M3000, designed to work wirelessly with phones that include Bluetooth technology. It sells for about 140 dollars. There's plenty of competition. Shure, a well known name in the professional audio market, is now making a headset for mobile phones it calls QuietSpot. Marketing manager Chris Lyons... says the company has been making wireless in ear systems for singers and musicians for years...

"So we took one of our music quality earphones, added a flexible boom noise canceling microphone, and created a great sounding cell phone headset."

The QuietSpot, for Nokia or phones with standard headset jacks, sells for about fifty dollars. Bloomberg Boot Camp, I'm Fred Fishkin.