[Alan Vanhollebeke]

I've been using one for a few years in my racecar. I have the "long range" light mounted on a camera tripod.

Works great as long as some shmuck doesn't decide to bring his & set it up a hundred feet saway from yours.

Whenevre multiple ones are set up on the front straight at the track, we either try and just leave one on all day.......
or if one is much higher than another, suppose like one for a sedan & one for a formula car. WE turn them both on but have the sitting right next to each other.

They do make an excellent tool. Before I used them I used to just velcro a stopwatch (with front mounted buttons) to the center of my steering wheel.