CornerFills are sections of flat-cut Studiofoam corner acoustic absorbers that are beneficial in 2 ways. Aesthetically, they give you smooth, clean edges against which to butt your acoustic wall treatments and acoustic foam bass traps for a more professional appearance. Acoustically, they smooth out the excess low-frequency energy that congregates in room corners. Great for gyms and larger rooms. Includes 9 pieces (18 lineal feet).