can't read?
Potassium nitrate is a chemical compound with the chemical formula KNO3. It is an ionic salt of potassium ions K+ and nitrate ions NO3−.It occurs as a mineral niter and is a natural solid source of nitrogen.
P 2388 (OTTO) Potassium nitrate, 99.995% Cas 7757-79-1 - used as an electrolyte in a salt bridge, and as thermal storage medium in power generation systems. It forms phase change material with silica and alumina nanoparticles.