Cavius makes a compact, easy-to-use travel alarm. The Cavius has a 130-decibel alarm that offers 4-way protection. It acts as an optical smoke detector, for extra protection while staying in a hotel or anywhere that seems to be lacking adequate smoke detectors. Activate it while attached to your handbag, laptop bag, or luggage, and the alarm will sound if the Cavius senses movement when the bag is picked up, moved, or even rummaged. (There’s a 5-second delay to allow you to disarm if you accidentally jostle the bag.) Hang it on a hotel room door, and the alarm will sound if anyone attempts to enter. Finally, you can use it as a personal safety alarm to draw attention if you are attacked while walking, jogging, or working alone. The smoke detector can be used in conjunction with all other functions. Cavius is in Denmark, but Amazon.com sells the Cavius alarm in the US for $79.00.