A wonderful Keralan drum, its full name is Shuddha maddalam: always used for accompanying Kathakali dance, but also one of the Panchavadyam instruments (a percussion group consisting of 5 instruments). I bought one home from Kerala last year. It is very heavy. I don't know how these guys manage to take the weight on their back as they do, let alone play at the same time! Right-hand side is similar to left hand side of mridangam, but the outer rings are very heavy and thick and the inner skin is very tight like tavil. Left-hand side is akin to mridangam right-hand side, but the black circle covers almost all the face like khol but, again, construction is very heavy-weight with outer rings being made from buffalo skin much thicker than mridangam. Right-hand is played very like thavil, with rice-clay finger rings, left hand gives ringing sound with about four different strokes, including a continuous note produced by rubbing the finger tip on the face All the leather work is very thick and heavyweight, and the tension is very high.
I will add some photos including details of each end when I have taken and scanned them, but one good picture can be seen at David Courtney's site: http://chandrakantha.com/articles/indian_music/shuddha_maddalam.html