... to 20cm, with all kinds of metallic mesh, perforated metal, with frame of stainless steel, zinc or chromium ... Opening Sieves, Round Opening Sieves and Wire Mesh Sieves for Coal:(Wooden frame opening: 0. ... to 20cm, with all kinds of metallic mesh, perforated metal, with frame of stainless steel, zinc or chromium ... Opening Sieves, Round Opening Sieves and Wire Mesh Sieves for Coal:(Wooden frame opening: 0. ...