Phosphorus is translocated into fruiting areas of the plant where high energy is needed for the formation of flowers.  
Potassium helps flowers to form and also helps strengthen plant tissue. This also helps with the maturing of the flowers and trichome production. 
Sulfur contributes to the synthesis of essential oils & terpenes and plays a part in various metabolic processes that are crucial for maintaining the overall health and vitality of your plants. 
This part gives you the ability to manipulate phosphorous and potassium as needed during specific phases of flowering. 
Derived from Monopotassium Phosphate, Potassium Sulfate, Magnesium Sulfate.