The world Yantra means an Instrument.  

Vedic Yantras are geometrical figures constructed to represent gods, planets, astrological symbols etc.  Used in conjuction with vedic chants, yantras can be extremely powerful to deal with the many problems that the ancient science of astrology defines.  

All AstroKalyani Yantras are specially energized to suit the purpose and come with the special chants and instructions needed to use them properly.