Wet Spray Fiber Insulation comes in variable thickness levels can fill 2×4 cavities up to an R-15 thermal rating, 2×6 cavities up to R-23, and six-inch steel stud cavities up to R-25. The insulation also reduces sound transmission, achieving a Sound Transmission Class of 43 in a standard 2×4 wood-framed wall. The insulation also resists mold because it sprays in almost dry (less moisture content than wood framing), and is treated with a U.S. EPA-registered mold inhibitor to protect the insulation against mold. It can be used for both wall and ceiling applications. In addition, only fiber glass insulation made without formaldehyde and can pass Environmental Specification 1350, the toughest indoor air quality test in North America, with a non-detect for formaldehyde.