It's an IDE Hardwear encryption kit.
Basicly it uses those firewire looking things like keys. You format the hard drive with that key installed and forever after (Or untill formated without it.) will not be accessable unless the key is there. Ok example.
You live with a few room mates and you don't want them getting on your computer. You install this and now the only time your harddrive is usable is when you put the key into the dongle thingy. (I don't know what else to call it.)
NOTE: them keys are not easly replaced.
On the board you got there there is a set of jumpers
1 2 3 Defalt has it the jumper set for 1 2 and 4 5.
4 5 6
You can change the jumpers to any combitnation you want kinda like a combination lock. Now even if they get anther board to access the drive they still have to figure out your jumper setting. (Not hard, but time comsuming.)
When you format the drive with the key in, it sets the jumper information onto the key and the hard drives sector 0, basicly the format information area. Now when the key is in. The key puts in the combination and the drive is unlocked. If its the wrong key chances are its going to put in the wrong combo and it's not going to work.
NOTE: They combo will not take hold till the drive is reformated.
NOTE: Write down the jumber settings somewhere that is safe just incase someone tries to f-with it.
Well I hope I helped. And trust me it's not as hard as it sounds. It's as hard as replacing and IDE cable.