The name of this instrument is Gopi Yantra or Ektar. I bought this instrument ATC Building in Osaka south port. I do not know how to play it. The spherical resonant or the round part that has leather is made normally from wood, coconut, or pumpkin. The 2 sticks that are attached to that are normally made from bamboo. The chord can be tuned by that thing that is on the top. The sound can be varied by playing the chord with one finger and approximate and step back the sticks.