Desiccant, 450 gm moisture absorber box, re-usable unit automatically absorbs humidity inside safe, protects valuables, papers & metal products from corrosion, especially firearms, simply heat in oven to reactivate.Specifications and Features: PROTECTS FROM CORROSION: absorbs moisture from within enclosed storage spaces and safes. RECHARGABLE AND EASY TO USE: Simply heat in oven to reactivate. BUILT IN INDICATOR: Once saturated the indicator turns from blue to pink. NOT JUST FOR CORROSION: Stops mildew, rust, mold and musty odors from happening.