... turns from blue to red,visually indicating the relative humidity of the given environments.When being used with ordinary silica gel or drier ... used as silica gel drierfor the packing of precision instruments, leathers, shoes, clothes,foodstuffs, medicines and household electric appliances,etcSilica Gel Blue Indicator Bead ... PP Bag, 25Kg Fiber/Iron Drum,500Kg, 800Kg Container Bag blue silica gel