Budget Travel recommends eAlarm Plus [-_-]

Credit: ​https://www.budgettravel.com/article/gifts-tech-gear

"​Increase Your Security Detail"

For that fearless traveler who boldly ventures through dark alleys and dodgy neighborhoods—or bear-infested woods—in search of the next adventure, stay safe with an itty-bitty personal alarm. Barely three inches long and under an ounce, Basu’s battery-operated eAlarm+ comes with a carabiner and clips to a daypack or keychain so you'll always have it close at hand. It’s easy to use too: Pulling out the black pin at the end unleashes a 130-decibel siren that will sound for half an hour, or until the pin goes back in. A reliable companion for late-night city strolls, you can also use it with cords to set a tripwire perimeter around a campsite, or string it up on a hotel-room door for extra protection against intruders.