The Federal Trade Commission is seeking to block what it calls false advertising by the makers of a radio-wave device that purports to provide "permanent hair removal."

Some people have spent up to $6,000 for "a series of unsuccessful treatments" with the "Removatron" device, the FTC says. It is generally sold to beauty salons, who in turn sell treatments to their customers. The FTC says at least eight other companies make similar devices.

In a complaint filed earlier this month, the FTC alleges that Removatron International Inc. of Boston falsely claims that another branch of the government, the Federal Communications Commission, has endorsed the device. "In truth and in fact, [the FCC] . . . has merely approved the operation of the Removatron device at a certain frequency to ensure noninterference with radio broadcasting," the complaint says.

Removatron has denied the charges. "It has been clinically tested," Frederick Goodman, Removatron's chief officer, says. "We have hundreds of letters from satisfied customers."

Ads for the device say it is more effective than electrolysis, in which hair roots are heated and destroyed. The Removatron claims to work by "heating hair roots through radio waves transmitted from the device to individual hairs by electronic tweezers," the FTC says, adding that the device may work to eliminate hair temporarily.

The FTC estimates that consumers have spent about $37.5 million a year to have hair removed with the device.