Factory. Fire protection A1,heat insulation, harmlessness, used for fireplace, stoves, wall, firedoor core, pipe protection... It is made of expanded ... Material: Expanded vermiculite2 Working temp:1100degrees3 Advantage: Natural, environmental-protection orientated, no poison and no radioactivity Fireproof, damp-proof ... Any size can design as your need. evironmental protection vermiculite board