American firm Under-Tech has launched, Under-Ease pants, the world's first pants with built-in underwear designed to contain the smell of farts. The Web site of the company claims over 10,000 satisfied customers have tried and tested the new product.

Buck Weimer, President of Under-Tec and inventor of the pants said the underwear has a built-in, multi-layered, replaceable filter made of felt, charcoal and fiberglass wool that traps the smell of flatulence.

Weimer said, "Under-Ease are underwear for protection against bad human gas. We get a lot of jokes - but we don't doubt that this is a serious product that serves a purpose."

"They can be worn anytime, anywhere - in bed, to work, at social events, including professional meetings or when traveling in any vehicle, including an airplane."

The underpants are made from air-tight fabric and completely sealed with elastic around the waistband and legs, that effectively prevents gases from escaping.

Weimer said the pants are washable and the replaceable filters will take several weeks to months before needing replacement.