Portable door lock.

Are you living in a dormitory or apartment with Nosy landlords? Make sure that door doesn't open without your permission by using the Add-A-Lock. A simple mobile door lock that easily installs on most doors in seconds. This device gives you the privacy you need by making sure the door doesn't open even if the person outside uses his key. Bring it with you on your travels to keep your hotel room extra safe.

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Buy on www.amazon.com
Under $25