... proof, water proof, aging-proof, shock proof, crack proof, sound insulation, save 15%~30% construction cost. Magnesium oxide board is ... Resistant to deformation in wet, hot and dry condition 6) Sound insulation: Sound absorption through a 6mm thick Tolar TM plate - 29dB 7 ... wet condition2) Expansion coefficient is above 8/10000, water absorption rate is 35%2) With good moisture resistant performance, ...