Odyssea Bio Glass Rings Canister Filter Ceramic Media for Aquarium Pond with Mesh Bag

I mean as far as I know they are working I used this in a new canister set up and so far can't complain they was old as far as the date but don't matter I don't think

They work pretty good . Just remember to pre soak or rinse.

Ceramic, not sintered glass. Bad labeling.

Very good