We have assay of 98.5% and 99%;Phosphorous acid is mainly used as reducing agent, nylon whitening agent, pesticide intermediate and raw material of organophosphorus water treatment agent; it is widely used as raw material for manufacturing phosphite, raw material for manufacturing plastic stabilizer in plastic industry, reducing agent in chemical reaction and synthetic fiber; CAS is 13598-36-2;package is 25Kg/plastic woven bag. It is shipped as class 8 dangerous goods.