I’ve had the chance to direct some traffic in my days, and one thing that’s an essential part of every traffic control kit are those battery operated flashlights with cones on the end – marshalling wands. Marshalling wands provide visibility for lowly mall security traffic control all the way up to ground traffic controllers at every airport around the world. Some of these are simply Maglite flashlights with cones attached to the end, but most airlines and airports use purpose-built wands. One thing that they all have in common? They all use batteries. Usually C or D cell, and they generally burn through them pretty quickly.