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Whether you’re traveling alone, staying in a hotel or want extra home security, this little gadget has your back.

All you have to do is open the door and place the right-sized hole over the strike plate, then close it so the metal plate is stuck. Then you use the red lock to secure the whole thing in place, and voila! Once it’s in place, the lock can keep intruders from opening the door from the outside, even if the door’s own locks are unlocked. (If these instructions are at all confusing, there’s a very straightforward video tutorial on the product page.)

Made with stainless steel and high-quality plastic, the door lock is durable while still being lightweight and easy to throw in your bag so you have it handy while you’re out and about. One reviewer compared it to the size and look of a bottle opener, for reference. It takes only seconds to install and remove the lock, so if you do find yourself in an emergency situation, you can easily and quickly secure a room (or unlock it to get out).

One parent who bought this for their child shared that it kept her safe when a maintenance man tried entering her apartment without notice. “The landlord hadn’t notified my eldest and had just handed the maintenance guy the master key to do the work, but because of this device, he hadn’t been able to do so,” they wrote. “I shudder to imagine a worser scenario that could have happened, but I and my eldest were grateful for the gut-feeling purchase I made. I now have one for each of my kids, my own mother, and myself.”

A solo traveler also found the lock useful when staying in an Airbnb that had no knob on the door. “Around 2am, I heard people walking by my private side entrance and shortly after they started jiggling the door and making it known that they wanted to come in,” they wrote. “They N E V E R made it inside due to this product being used. If you are a solo traveler PLEASE get this. I don’t go anywhere without this product anymore. Thank you from the bottom of my heart to the inventor of this product.”

“Works great and use it in every hotel we go to. In fact when we were in Europe, for some reason housekeeping just likes to open your door and not knock beforehand. This happened in multiple hotels in Europe by the way. This prevented them from coming in on us without notice.

One time housekeeping kept trying to get through the door thinking it was a fluke but realized we had secured the door well with this device. Highly recommend so you can feel safe in your room.” —Holl

“This product came in handy during my airbnd stays. Onetime the person overseeing the building I was staying in thought I was smoking in my room and tried to come in unannounced and bc of this extra lock they could not come in even with a key. I was in bed in my birthday suit. That would have been a very uncomfortable situation if it wasn’t for this lock. The owner apologized after and upgraded my room.” —Rema

“2 months at our new apartment and i’ve finally found a way to lock my bedroom door without the hassle of tools and removing the knob. I feel at peace knowing I won’t be barged in on and that there’s no outside lock to be picked. Very durable and strong lock. Only needed the door locked when here, so it’s perfect, and i will definitely take it with me when I start solo traveling.” —Z

“We took this with us to Peru and it was a godsend. Luckily, there wasn’t any reason that we needed up needing this (aka no one tried to break in) but the front door of our air bnb didn’t lock, only the bedroom doors. So this was great to have as we used it on the front door as well as the bedroom door. Works EXTREMELY well. We tried to “break in” with it and it was sturdy. Light weight, so it didn’t take up precious points in the suitcase. Fairly simple to use once you get the hang of it!” —Amazon Customer

“My daughter has been doing some travel for work. I saw this product recommended a few times and I sent it to her ASAP. She laughed about me being overprotective but her last trip was in the Canadian wilderness and one of her trainees got inebriated after hours and came to her hotel harassing her. She was so grateful for the added protection. It’s small and she said it wasn’t complicated to use but tested it at home first. Who’s laughing now?” —Selina

Reviews have been edited for length and/or clarity.

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