HARTFORD, Conn. — Entering an empty, unfamiliar house with a stranger is all in a day's work for real-estate agents, most of them women.

"You're on your own," said Nicholle D. Dagata, a real-estate agent in Berlin, Conn. Cell phones are an obvious tool but cannot be used inconspicuously and can drop out of range in a basement, she said.

"Sometimes you feel queasy."

Now, GE Security's new wireless lock boxes, already designed to quickly notify a seller's agent that a house is being shown, are being outfitted with a "panic button" agents can use in an emergency, starting early next year.

GE Security, a subsidiary of General Electric Co., announced the feature Wednesday at the National Association of Realtors convention in Las Vegas.

Violence against real-estate agents is rare but includes assaults, robberies and even killings, according to the National Association of Realtors. In 2005, 2.5 percent of real-estate businesses reported incidents of workplace violence, according to the U.S. Bureau of Labor Statistics.

GE Security expects that by the end of the year, more than 130,000 agents in about 30 markets will be using ActiveKEY, the wireless lock boxes GE Security introduced in August. The boxes cost agents $11 a month, which will include the panic button.

The service, provided to members of local real-estate associations and Multiple Listing Services, is touted as giving them an edge.

Traditional lock boxes have a lock combination and hold a key to the house, allowing agents to show the house and leave behind a business card, but not do much else.

With ActiveKEY, a seller's agent knows when a house has been shown, and a buyer's agent can get extra information about the home — or even instructions to not feed the dog.

The panic-button feature is expected to appeal particularly to women, who the National Association of Realtors says make up 64 percent of the workforce.

The device alerts as many as five emergency contacts and sends them the address of the last lock box the agent opened and a message programmed by the agent.

The agents also can exchange comments about the house from potential buyers, which can help sellers make improvements or decide when to cut the price to sell the property faster.

"It's making it so that Realtors can work more efficiently in a market where having information quicker means selling the house," said Nancy Brown, an agent who works for GE Security. "We want to get them in the house, see the house and sell the house."