Underlay 4mm Rubber

Thickness :4 mm
Water resistance : waterproof
(Moisture can not penetrate closed cell membrane)
water absorption :0.003 lbs per cubic feet
Density : 110kg /cubic m
Sq Ft per Roll : 200 Sq. Ft.
Thermal Conductivity : 0.25 BTU/hour/sq.in. 
Fire resistance : UL 94 HFI,F,A,R,25.83
IIC Rating : 76db 
STC Rating  ：77db
(condominium  approved)