Montgomery County authorities have added a new weapon to tame inmates who threaten to become unruly in court: stun belts that can deliver 50,000 volts of electricity in eight-second doses.

Activated by a remote control, the jolt is sufficient to make a muscular 250-pound man collapse, writhing and screaming in pain.

Montgomery sheriff's officials say they need the belts -- they have purchased three for $800 each -- to protect judges, lawyers, jurors and the courthouse public from the 1 or 2 percent of especially violent jail inmates who attack corrections officers or make threats toward judges or court officials.

In the last three months, the belts have been placed on inmates 10 times, but no one has been shocked, officials said. But some defense lawyers and civil rights activists said the electrical belts deliver punishment that is too severe and could be abused or cause serious harm if the belts malfunction.

"Is it like a shock collar?" asked Stephen Meehan, a Maryland defense lawyer for Prisoner's Rights Information System of Maryland Inc., which represents state prison inmates. "We use those to train dogs."

Stephen A. Friedman, legal director for the Prince George's County chapter of the American Civil Liberties Union, called the belts "frightening."

"There's something called cruel and unusual punishment," Friedman said. "What would warrant it? Maybe the defendant stands up and yells at the judge. Does that require 50,000 volts to the midsection?"

Sheriff's officials concede that the jolt is extremely painful. The shock from static electricity of shoes rubbing across a carpet is 25,000 volts. Double that and count for eight seconds.

Sgt. Michael Godwin, who received a jolt from a stun belt as part of his training to become an instructor, described the feeling as: "If you had nine-inch nails and you tried to rip my sides out and then you put a heat lamp on me." Afterward, he said, he felt fine but his muscles were fatigued, as if he had just worked out for 20 minutes.

A video produced by the belt's manufacturer, Cleveland-based Stun Tech Inc., shows burly police and corrections officers getting a jolt and dropping to the ground, where they flopped around like fish and screamed obscenities.

But Chief Deputy Darren Popkin said yesterday that the belts are necessary for the relatively few inmates who can't be controlled.

The belts are also in use in Harford County and Baltimore, he said. The Montgomery sheriff's office bought three belts in September after an inmate caused a "brawl" in a courtroom with five deputies trying to subdue him after he hit his attorney and bit a deputy. When he appeared back in court for his trial in October, the belt was strapped beneath his suit, where the jury wouldn't see.

"He was completely compliant, and we had no problems with him," Popkin said. "These are dangerous and combative people we deal with. . . . It's psychological deterrence. The anxiety of having it on seems to be the most effective tool."

Inmates must wear the battery pack, which is about five inches square, resting against the middle of their backs, just over the left kidney. They are then given a form telling them that a deputy with a remote transmitter could shock them if they make any "quick" or "hostile" movements, tamper with the belt, hide their hands or disobey a command. The inmate may get a warning beep first.

The electricity pulses through muscles but does not affect any organs, Godwin said. Even so, inmates must first be screened by jail doctors to avoid anyone who is pregnant or has heart problems, epilepsy, muscular dystrophy or multiple sclerosis.

Local defense lawyers say they worry that deputies are given too much discretion to decide when to inflict pain. A lawsuit pending in California alleges that a judge ordered a deputy to administer the jolt to make an inmate, who was representing himself in court, stop talking.