Thudi stands between Udukku and Idakka in terms of size. Though not a "kshetravadya" (percussion instrument used in temple), it is used as accompaniment for "aandi nritham", a ritualistic dance performed in Devi temples. In the past, members of the Panar community used it for the "thuyilunarthupattu" during the Onam festival season.
The two membranes on either sides are large in size while the middle portion of the trunk is slim. Skins are stretched over the metal rings fitted to either sides. They are fastened with laces that are inserted through the holes on the rings. The instrument is played on one side by suspending it from the shoulder of the artist. The tension of the skin is adjusted with the help of the lacing.