The moment she picked up the phone, she knew something was wrong.

The heavy breathing, the quick footsteps, the panic in the caller’s voice.

Abby Singh, a social worker and children’s program manager at My Sister’s Place, the District’s oldest domestic violence shelter, offered to call the police, a ride, anything that might help.

But the woman, in Southeast Washington to look at an apartment, wasn’t sure of her address. She was being followed by three men, she told Singh. She called the shelter because she didn’t want to dial 911 — wary of involving police because she is an immigrant, like many of the shelter’s clients.

The call lasted five minutes, Singh said, but it felt like an hour. Every moment until the woman was safely on her way to the shelter seemed to play out in agonizing slow motion.

When survivors of domestic violence flee their abusers and seek the help of an organization like My Sister’s Place, they are often encouraged to draft what experts call a “safety plan.” It maps out preventive measures, important contacts and what to do in an emergency. What can be challenging, shelter workers said, is helping survivors prepare for the moments in between — when they’re not at home or work, when they’re somewhere unfamiliar or in a situation they did not anticipate. That’s what happened to the woman on the phone.

The next day, My Sister’s Place got word that an entrepreneur was donating a new tool the shelter hoped could help in moments like these: a panic button that can call for help — immediately and discreetly — with the push of a button on a keychain.

“The minute we got them, we started handing them out,” said Mercedes Lemp, executive director of My Sister’s Place. “From having worked with survivors, safety is always the number one priority. But with the trauma, feeling safe can be difficult, so having something that at least gives you a little bit of a peace of mind is a big deal.”

The device, called the Silent Beacon, relies on Bluetooth technology to connect to a phone and alert trusted contacts, trace the user’s location using GPS and, if need be, notify police. A built-in speaker allows for two-way communication, or for the person on the other end of the line to listen while the gadget is muted in especially volatile situations.

Created by Kenny Kelley of Potomac, the device is meant to help the wearer feel safer. Kelley, a former stuntman, conceived of the idea after he suffered an accident and couldn’t reach his phone to call for help.

One day, while listening to a news report about a woman who was on the phone with police when she was forced into the trunk of her car and abducted, Kelley said, he realized a buttonlike device could help protect against acts of violence and abuse, too.

“I was like, ‘Gosh, if there was just a way where you could — blip — press a button and then . . . everyone in your circle could know where you were and that you were in an emergency right away,’ ” Kelley said.

Similar smart panic buttons exist, though their features and prices differ greatly.

Many low-cost options are confined to apps downloaded to a person’s smartphone. Some that function as a separate button have the capacity to call only 911, rather than a preset list of contacts.

Pricier versions use their own cellular connection but charge users a monthly subscription fee.

Kelley, who rolled out the first Silent Beacon devices earlier this year, said physically separating the button from the phone was important to him so people in a stressful situation wouldn’t have to worry about finding or activating their phone. Because the button taps into the phone’s cellular capabilities, the cost is a one-time charge.

Kelley reached out to My Sister’s Place in October and offered the shelter a year’s supply of Silent Beacons. The shelter serves more than 100 families each year by providing emergency shelter and transitional housing.

It’s the first domestic violence shelter with which the company has partnered, Kelley said, though he hopes to use the relationship as a model for future nonprofit collaborations and to devise new ways to serve domestic violence survivors.

For Debra, 27, who spoke on the condition of anonymity for fear of being found by her abusive ex-boyfriend, the device has replaced pepper spray in her self-defense arsenal.

In federal buildings, which Debra enters regularly for work, and in some states, pepper spray is not allowed. But the little pink button attached to her keys barely gets a second glance.

“At first, I was like, ‘This little thing? How can it function?’ You know, ‘What can it really do to protect me?’ ” she said.

Debra, originally from Maryland’s Eastern Shore, came to the District earlier this year after a relationship turned violent. Her ex-boyfriend followed her. She got a protective order but still found herself looking over her shoulder, worrying for her and her daughter’s safety.

She was one of My Sister’s Place’s first clients to receive a Silent Beacon. She carries it everywhere.

“It makes me feel good,” she said. “Like even when I’m out walking by myself, I’m not really alone.”

Lemp said no one has had to use the device in a real emergency. But, she said, it brings a sense of comfort to survivors who often struggle with fear, anxiety and post-traumatic stress symptoms.

“It’s sort of like, if you have a house and you have a house alarm and you have it on, you might sleep a little bit more comfortably,” Lemp said. “It doesn’t mean nothing is ever going to happen, but there’s an added level of security that comes with just knowing the alarm is there.”