... . Graphite blocks: goog quality , long life , low noise 2. Apply to heaters,heat shields,crucibles , boats.etc MATERIAL: Extruded Graphite,Molded Graphite,Isostatic Graphite,Vibration Graphite,High density ... ,heat shields,crucibles , boats monocrystalline silicion furnaces , sintering moulds .2. High density graphite block. Apply to precision tools , war/chemical/smelt industry. etc ...