USB device that can send keystrokes?

For some security testing, I am looking for a USB device that can send
pre-programmed key strokes
when plugged-into the USB ****t. Any suggestions?

I want something that doesn't require a software/script to be loaded
on the computer.

Something along the lines of WiebeTech's MouseJiggler <
http://www.wiebetech.com/products/MouseJiggler.php
>, where it just
sends the mouse commands without loading any software.

Or maybe a programmable keyboard that can send keystroke as soon as it
is connected, without requiring any software/script to be loaded.
Obviously this device would require a built-in processor and some
memory.

saqib
http://doctrina.wordpress.com/