This desiccant is a distinct blue color. When its drying capacity is exhausted, it turns to pink. Indicating DRIERITE gives constant visual assurance of active desiccant.
Product SDS Sheet
Note: Desiccant Driers should be changed regularly - if fully pink they are not working and the FSII/PRIST/DiEGME may not save the aircraft from ice in the fuel system and may even cause damage to the aircraft's fuel tank. Research has shown that if just 0.5% of water gets into the FSII, it will not dissolve into the fuel! It will sink in the fuel and attack the tank bottom. Water contamination can simply be from simple condensation in the airspace is the reservoir. This is why a desiccant drier is used. Non-dissolved FSII is a powerful solvent that attacks aluminum, steel, tank linings, and Viton and Nitrile rubber.