What does this Databreaker do? Well, it plugs into your AC outlet and acts as an Ethernet intermediary between your PC and a router or modem. After a few minutes of non-usage, the Databreaker kills your connection so no traffic can go in or out of your PC.
The only reason anyone would use this is if their computer is so far gone from Spyware or adware that they can't really fix it by themselves, and want to kill off their internet connection when they're not actively using the machine to protect from "Hackers". Otherwise, just enabling or disabling your network connection on your computer would accomplish the same effect, saving your $40 in the process.