Roberts 70-190 Super Felt Insulating Underlayment, 4 Mm T, 27-1/3 Ft L X 44 in W, Recycled Fiber, 100 Sq Roll, Green N/A Imported Provides deep, rich sound by absorbing noise instead of deflecting it Made from recycled fibers Extremely high temperature manufacturing process treats fibers 3mm thick pad corrects minor sub-floor imperfections IIC 67, STC 66 ? Rating 21