The Dhruva Nano Zx is a harmonium-type drone sruti box (sur-peti) that is also a Tuner / Metronome / Tuning game. It is NOT a digital tambura / tanpura!   It produces a drone similar to a harmonium type traditional sruti box (sur-peti). It has a Tuner / Pitch-pipe with Digital Display, Dual scale system: Chromatic / Diatonic. A new feature in the Dhruva Nano Zx is the tuning game to help improve your tuning skill. Other Features are: –  Auto-tuning of SA-PA-SA / SA-MA-SA with LED indication –  Pitch adjustable over 1 octave and Fine tuning of pitch is available –  Also has an optional Metronome –  Automatic switchover to batteries on power failure –  Automatic saving of selected pitch into memory; option of saving one more selection into memory –  Tiny – palm-sized (size:115mm x 130mm x 80mm, weight:approx 0.5kg) Plus all standard Radel features: –  SMPS Universal Voltage (90V – 260V AC without voltage selection) –  3 year warranty –  Renowned Radel after-sales service