DRIERITE Desiccant Cartridge - 15C381C
Since iso crystallizes with moisture, it's important to keep the two from meeting. If your iso hardens up inside your drum, that just means you will probably suck it up into your system, creating pressure loss as well as some other headaches.
The best ways to prevent this is to not let the moisture into the drums. This desiccant cartridge will dry the air before it ever enters your drums, preventing a thin layer of iso to harden, and eventually going through your system.
Remember once the blue beads turn pink, it's time to replace the cartridge!