Selenium is a important trace element , it can increase the egg, hatch and growth rate of birds; to livestock , it can increase the use rate of feedstuff and cure some disease, it also accelerate the growth of fish. SPECIFICATION- Physical Appearance: Creamish White Powder Assay: 99.80% min Se Content: 45.0 %min Lead: 30ppm max Arsenic: 10ppm max Loss on drying: 1.00%max