Cal-Flor FU81422 SilverStep Premium Cross-Linked Polyethylene Foam Underlayment and Moisture Barrier for Floating Laminate and Engineered Floors, 100 sf, Blue Double protection: 3.2 mm cross-linked polyethylene foam with added film barrier Superior sound-dampening: IIC 72; STC 66 Accordion folded ensures that underlayment will lay flat during installation Positioning tape seals out moisture and speeds up installation Unfolds to 28'x43x3.2mm for a total of 100 sf