i use these to dry. i put one in a 2x2 tent with a booster fan in top exhaust port and intake screens open. the fan is dialed down to 70-90w with a variac. we want to air to slowly be pulled through the flowers, but no too slow that mold could be an issue. too much air flow and the flower dries too fast.
the most important part, the room this tent is in must be proper temps and rh. typically 65-75F and 60% rh is where mine is, then drop to 55% rh after 5-7 days. After another 4-7 days its ready to be burped in a properly sized container.
I bought one of these, used it for one grow and never used it again. It just doesn't fit into my drying/trimming/curing process as well as hanging the whole plant.