Product review (3 stars): rust over time
These evaporative panels work really well but the outside frame is steel and will rust over one season.  It could have been made of PVC so It would last longer.  The alumnum mesh inside could have been made of plastic.  It will corrode if harsh cleaners are used on it, like sodium hydroxide (lye).  I find that I need something strong like bleach or hydrochloric acid to kill off mold that can grow on these panels.  As a result I have to order new ones every year so I can keep my family healthy.