... materials - walnut shell grains. Compared with the old pore-forming material-- refined naphthalene ... ] walnut shellAppearance:shiny ,beautiful, brown. High-quality fruit (coconut, apricot) shell as raw materials ... vapor activation crumbs.Features: developed gap, good adsorption properties, high strength, easy regeneration, ... , electronic parts, etc. different size Walnut shell used as polishing material