These unfaced fiberglass batts are ideal for insulating and sound proofing ceilings or 2' x 4' stud wall cavities with 16" on center spacing (exterior sidewalls, basement walls, floors, garage walls and add-on insulation in attics). It features friction-fit in-wood framing. Glass fiber will not settle, rot, mildew or deteriorate. Rolls can be cut to any length. This product has been GREENGUARD® Children and Schools certified for superior indoor air quality. Third Party Certified Recycle Content.