This is a simple chess clock. It can also function as a normal timer. To start the clock for the first time or to pause/resume the game the mouse must be used, otherwise any keyboard input will switch the clock over from one player to the other. When time expires on one clock the screen lights up red to make it obvious time has expired.
Try to be gentle with the keyboard. The jar can be found here. If you're interested in the code email me for details.