Hello all. I am wondering if anyone out there has used a Reptile Humidity Indicator by Four Paws? If so can you tell me how they work i cant quiet seem to understand how it works and there is no indication on the box explaining. Thank You All. Have had my crabs for just over 3 weeks now and they are coming along great, i think i have one molting and three have been through several shell changes. They are funny little things and we love watching them at night.