Silicone hole is the number of hydroxyl groups (a polar group, very close to the structure of water), so he can absorb large amounts of water. Like activated carbon, the same hole, but almost no water absorption, because internal carbon atoms are hydrophobic. Large-pored silica gel used as toothpaste abrasive material, catalysts, matting agents, and so on. So choose according to the different uses of different varieties. Silicone is used as a desiccant, and reuse.