On-board timer for drag racing???

Didn't know where else to post this. But I remember watching a show about modifying trucks a couple weeks back. I know what you're probably thinking...trucks on a honda forum??? But on that show, the guy hooked up this device inside the truck that was able to give him his 1/4 mile times and speeds. Basically, from a dead stop, once he presses the throttle, the device would begin motoring the speed and length of road the truck has traveled. Once the truck has traveled a 1/4 mile, it would post up the stats and he'd stop and start over again. I didn't get the name of this device but I thought it was pretty cool. Does anyone have any clue as to what I'm talking about? And do you know where to get one of these? I wouldn't mind purchasing one and finding a dead straight and flat road and practicing on that.