Add this official Stern fire button to your machine to easily allow you to fire balls that are locked in to guns/cannons and harpoons etc (ACDC, Ster Trek Next Gen, Dirty Harry to name a few). In addition the fire button doubles up as a START GAME button which is super handy. The fire button is LED lit and those LED's are controlled by the table you are playing. For example when playing Stern's ACDC the fire button will flash when ready to fire. As more and more games are releaed that require the fire button this upgrade is a must.
If you do not have the fire button upgrade you use the START button on the front of the machine to fire the balls.