I got an on top coffee filter as a free gift and (stupidly) tried to use it with my favorite, very large, coffee mug. It just about fit and I should have known better than to trust it was safe. Somehow I caught it just after pouring on near boiling water and scalded both my legs as it tipped all over the floor!
This is the closest picture I can find. Mine is a different brand and made of plastic. http://www.amazon.com/Frieling-C104943- ... pd_sbs_k_5