Compatible with all systems, these Desiccant Canisters are located on the underside of the Tank Lids. This unit dries the air prior to entering the tank. These have a circle located on the face of the unit. When new, the circle is blue, when the circle turns pink it is time to change or dry out the desiccant beads. See the package instructions on the new canister for drying process. ****NOTE: If any A or B material gets on these canisters, they are to be immediately disposed of and replaced.****