floorMuffler® FLEX 10.0 is a high performance Acoustic Underlayment for use in residential and commercial flooring applications. As part of our Premium Collection, floorMuffler® Flex 10.0 is the ideal choice for most Laminate, Engineered and Solid hardwood flooring installations. floorMuffler® FLEX 10.0 can be used in Floating, Nail down, and Double glue down installations.