Twin Pack Of Rechargeable Dehumidifiers When fully absorbed the indicator window turns pink and the weight will have increased by approximately 120g. Simply plug in overnight to regenerate. After about 10 hours the window will turn blue and the dehumidifying force will be as good as new, ready to work again. These compact Rechargeable Dehumidifiers will help to keep your precious items safe from the damaging effects of damp and condensation. They are extremely versatile, with no batteries or wires required, making them ideal for use in small areas such as drawers, storage boxes and cupboards, wardrobes, bookshelves, car boots, bathrooms and on window sills. 100% renewable, non-toxic 'water glass' silica gel crystals are used to soak up the moisture, when dry the indicator shows blue and turns pink when it has soaked up the maximum volume of water. Simply plug the unit into the mains overnight and it will dry out, ready to use again - no mess or expensive refills!