You are able to do this Shabar mantra chanting for 11, 21, 31, or 41 days, the location and time of mantra chanting should be precisely the same for the number of days you need to do sadhana. You can use Rudraksha or Tulsi rosary to chant the mantra. https://vashikaran65318.mdkblog.com/38132840/the-smart-trick-of-most-powerful-sarv-karya-sidh-shabar-mantra-karya-siddhi-shabar-mantra-most-powerful-shabar-mantra-that-nobody-is-discussing