This is an interesting invention. The idea is that this lock lets you lose a key and simply use the next one in a preset series — no need to find the old one, it won’t work once you “pair” the new one. It works by using the new key to knock a little disc out of the way of one of the pins, changing the “combination” required to open the lock.
Of course, if you lose your keys, you still can’t get into your home. But this does simplify the process of changing your lock. It’s also proof against bumpkeys, so you don’t have to worry about that.
You can see a video of how it works here.
[via Reddit]