Brand new, unopened, set of 5. EM was developed in 1980 as a technology to achieve stable production of high-quality agricultural products that contribute to health and sustainable environmental conservation agriculture. It is a mixed culture of microorganisms that combines mutually beneficial, safe microorganisms such as photosynthetic bacteria, lactic acid bacteria, and yeasts. A major feature is the synergistic action of the lactic acid bacteria and yeast fermentation power, and the photosynthetic bacteria's synthetic power.