Rockwool Comfortbatt® R14 SS (3.5") x 16.25" 65.0 sq. ft/bag) Thermal Batt Insulation (Specific for 2x4 STEEL framed walls spaced 16" apart) R-Value: 14 Dimensions: 3.5" x 16.25" Coverage: 65.0 sq. ft./bag Application: Interior Walls Rockwool Comfortbatt® R14 Roxul for 2x4 STEEL STUD walls is a mineral wool insulation made from a combination of natural basalt (or volcanic) rock and recycled slag. This is an alternative to fiber glass batt that is non-combustible (melting point of 1177° C), sound reducing, and moisture resistant. As an alternative to fiberglass, this mineral wool insulation is easy to cut and maintains its R-Value after compression during installation. This product is designed specifically for friction fit into wall partitions and system applications from party walls to plant/manufacturing walls.