Sound Balance acoustic tile, dark grey, set of 2. Absorbs sound, optimising the acoustics in open-plan offices. Acoustic efficiency: sound absorption class B, sound absorption coefficient αw = 0.80 (sound absorption coefficient αw as determined by DIN EN ISO 11654), tested and certified by Müller-BBM, an independent institution for acoustic assessment. With original tesa® adhesive strips pre-mounted on the back, the tiles are mounted without drilling and can be removed and repositioned as required. A new set of adhesive strips (SB190) is required to reposition the tiles. Each tile is 400x400x42 mm in size. In combination with other sizes and colours from the acoustic tile range, the tiles are ideal for covering large areas.