It looks like a small headphone but fits around your bare ankle.

Known as the Secure Continuous Remote Alcohol Monitor — or SCRAM — the device measures blood-alcohol content that naturally dissipates through perspiration.

Thousands of convicted drunken-driving offenders in 40 states — including North Carolina — wear the devices 24 hours a day as part of their probation, the manufacturer says.

But it is not used in South Carolina.

The Palmetto State has been slow to implement technology to combat drunken driving.

For instance, since 2000, South Carolina has permitted “ignition interlock” devices to be installed on offenders’ vehicles to prevent them from driving drunk. However, the device has not been used yet in South Carolina because the State Law Enforcement Division has not developed regulations for it, an investigation published Oct. 29 by The State newspaper found.

Ignition-interlock devices require a driver to blow into a small alcohol sensor that typically is attached to a dashboard. The car will not start if the driver’s blood-alcohol level is above a certain level.

Forty-four other states have laws allowing or requiring the devices, according to Mothers Against Drunk Driving.

State Law Enforcement Division Chief Robert Stewart has said his agency has not received enough of its share of fine money over the past several years to develop the ignition-interlock device program.

In November, MADD called on all states to require the devices for convicted drunken drivers, contending more than 1,900 lives nationwide would be saved every year.

The organization also announced the formation of a panel of representatives from MADD, the federal government and the auto industry to study other technologies, such as SCRAM devices, to prevent drunken driving.

“We are very optimistic about all kinds of emerging technologies,” MADD spokeswoman Misty Moyse said.

She said MADD has endorsed interlock-ignition devices because “research proves they are effective.”

State Rep. Garry Smith, R-Greenville, said he is working on a bill that would make it easier to use the devices in South Carolina.

“There’s no sense reinventing the wheel,” he said. “We can go to other states, like Pennsylvania, and get their regulations.”

Smith said he also is working on legislation that would allow SCRAM devices in South Carolina.

Typically, judges order convicted drunken drivers to wear the device as part of their probation. If it detects that offenders have been drinking, they risk having their probation revoked and being jailed.

“If they’re not drinking, they’re not drinking and driving,” said Will Sagar, president of Carolina Monitoring, a Columbia company that would market the device throughout the state.

But Greenwood lawyer Rauch Wise, who has worked for the state chapter of the American Civil Liberties Union, said limits on the use of the device are needed to protect offenders’ constitutional rights: “How long will it be before the Legislature determines that if you’ve got three DUIs, you have to wear it for the rest of your life?”

Under the program, offenders pay for the installation and use of the device. Sagar said his company would charge the typical offender $90 for installation, plus a $12 daily monitoring fee.

Reach Brundrett at (803) 771-8484.