Johns Manville Formaldehyde-Free™ Fiberglass Insulation (Specific for 2" by 4" WOOD framed walls with joists spaced 16" apart) R-Value: 12 Dimensions: 3½" x 15" Coverage: 97.92 sq. ft./bag Application: Interior Walls JM Formaldehyde-Free™ fiberglass insulation promotes better indoor air quality, provides superior thermal efficiency and a reduction in sound. Data Sheet