MAPEI Mapesonic 2 3.25-ft W x 49.2-ft L x 76-mil T Premium Felt Flooring Underlayment For Hardwood (160-sq ft/Roll)Mapesonic 2 reduces transmission of impact sound (such as footsteps and dropped objects) and airborne sound (such as voice and TV) through floors when installed under ceramic tile, stone, vinyl and wood floorings. It also helps to prevent existing or future in plane floor cracks (with movement up to 3 8" or 10 mm wide) from transmitting through grout, ceramic tile and natural stone assemblies. Boxed roll: 39 in x 49. 2 ft Sound reduction performance