The main composition of OUKPAK lime desiccant is CaO, which absorbed moisture by a chemical reaction. It chemically turns into calcium hydroxide by absorbing moisture. During the process, granules turn into powder, increasing 2 to 2.5 times in volume. Therefore the packets are made large enough to accommodate the fully swollen contents without puncture following moisture absorption.

Compared with the physical absorptive silica gel, it is a desiccant that has lower cost but higher quality, especially the rate of absorbing the moisture at the state of low humidity. Besides, it is good at absorbing the moisture for a long time, and the moisture that had absorbed will not return to the goods.

Reaction formula: CaO + H₂O = Ca (OH)₂