There are many derivative deities  from the Srividya.  The first of them is called Bala-Tripura sundari. She is imagined as young maidenor as a girl of sixteen , the mother goddess in her juvenile condition.






 Mantra of Bala-Tripura sundari. is,

AIM  KLIM  SAU

Or  

AIM KLIM SAU SAU KLIM AIM