Boom Mat Sound Deadening Headliner is now available in uncut 75" x 54" sheets. This universal sound deadening interior foam is an adhesive backed material that can be used to dress up any interior while minimizing annoying outside noise. Boom Mat Headliner is constructed of high quality marine grade acoustical foam that resists mold and mildew while insulating from outside heat/cold and sound with an R4 value.