This is a simple piece of SW, that does what it says on the can.

BUT!! When you buy it, you are only purchasing it for use on ONE machine - with a specific ethernet address.

If you need a new logic board, or you buy a new Mac, you CANNOT TRANSFER THE LICENSE. You need to pay another $10.

The author makes this very clear, but be warned.

Disk Utility now allows you to shred empty space - so I would stick with that.