We can make nano sliver ( Ag ) particles powder in ranges of 20~300nm at your requests. Usages nano sliver particles powder ( Ag )Appearance: Silver nanoparticles are black, no other color mixed, ball shape, no obvious agglomerate.It is anti-virus to kill the poison: The nanoparticle layer form silver department has no anti-virus powder in machine to have the very strong and anti-virus killing ...