They look like quite the contraption. 
They are pretty simple. I ordered the kit from their web site. Its pretty simple to make. Basically all it is is a rod holder, ya bend the tip over and hook it to an arm that has tension from a rubber band. The tension from the rod holds the tension of the rubber band. When a fish pulls your line, pulling the tip down, the rubber band pulls the arm out, allowing the rod to spring up and a flag pops up. I set the drag so when i pull the line toward the hole, the rod tip almost reaches the ice before the drag realeases, some time a little lighter.
