I just got my SP Diesel EST (Engine Shut Down Timer) installed. It pretty cool, it is adjustable from 0 to 10min and you don't have to arm it every time you get out of the truck like most other timers I have seen.

The timer has the ability to override the parking lights on while the timer is in operation. I really like that feature, its nice to beable to look out the window of my house or look across a dark parking lot and know if the truck is still running or not.