You are able to do this Shabar mantra chanting for eleven, 21, 31, or 41 times, the area and time of mantra chanting must be the exact same for the quantity of days you need to do sadhana. You may use Rudraksha or Tulsi rosary to chant the mantra. https://a-listdirectory.com/listings13065329/indicators-on-most-powerful-sarv-karya-sidh-shabar-mantra-karya-siddhi-shabar-mantra-most-powerful-shabar-mantra-you-should-know