396. 2,2'-Disulfandiylbis(pyridin-1-oxid)** (additiv s trihydrátem síranu hořečnatého) (pyrithiondisulfid + síran hořečnatý) Dithio-2,2'-bispyridine-dioxide1,1' (additive with trihydrated magnesium sulphate) (pyrithione disulpide + magnesium sulphate)***