If you're staying in a hotel that's kind of ... sketchy, then you might not be satisfied with simply locking your door when you're in for the night. You could wedge a doorstop of your own under it, but now there's a portable gadget that is claimed to work better – the DoorJammer.
Users start by placing the DoorJammer so that its vertical face is up against the bottom of the door, and its horizontal face is extending beneath the door. They then pull down its hinged leg, and tighten down its foot until it's firmly braced against the floor. Rubber coatings on both the faces and the foot help everything maintain a grip.
If someone should subsequently try forcing the door open from outside, the horizontal force that they apply to the door will be converted in vertical force, simply pushing the DoorJammer's foot more firmly into the floor.
In the event of an emergency such as a fire, the user can quickly remove the device by pulling up and back on its leg.
The DoorJammer is available now, for US$29.99. It can be seen in use in the video below.