Millions of Americans sleep in rooms on the second to the seventh floor. But home fire-safety ladders sometimes aren't long enough to provide an easy escape in case of emergency. Enter the LifeCender: a new, portable escape harness that allows a person to rappel down the side of a building. It comes in a briefcase-like box and goes on like a life jacket. Once the unit is anchored and secured, a person can control his or her descent to safety with a knob that monitors how quickly the cord unspools.