Spy Key Logger

The most common hardware computer spy gadget that you can get hold of is a keylogger. This device is connected between the computer and the keyboard. As the user types anything on the keyboard, such as emails, documents, passwords, etc, they are stored on an internal memory storage device within the keylogger. The owner of the keylogger can then retrieve the data from the keylogger at any time.
There are 3 main types of hardware keylogger available. There is the PS/2 model, which has the same fittings as a standard PS/2 keyboard. There is also the USB model, which is compatible with all modern keyboards. The third type of keylogger is one concealed within the computer keyboard itself. This is the ultimate in stealth as its very unlikely that a user would regularly unscrew their keyboard to see if a keylogger has been installed inside it. Keylogging devices can also work with some wireless keyboards as long as the keylogger fits between the computer and the USB keyboard receiver.
Hardware keyloggers are excellent for quick installations, but you do need physical access to a PC to install it. You also need physical access to the PC when you need to retrieve data from the logger.