i get free bottles of mammoth p my man, at my local shop they give out smaller bottles to promote the pruduct and 2 will last me 12 plants veg to flower. it helps the plants overall root system and in return helps produce thicker stems and healthier buds. i havent seen a significant increase in overall yield but i have noticed stronger stems and a healthier plant overall, as well as bigger bud sites. i havent done a side by side comparison but i used to not use it and i do now and i see a difference overall.