Sound dampening material on the back of the speaker (approx. 7.9 x 7.9 inches (200 x 200 mm) / thickness approx. 0.8 inches (20 mm) ... 4 pieces)
Soundproofing tape for speakers (approx. 0.8 x 23.6 inches (20 x 600 mm) / thickness approx. 1.0 inches (25 mm) ... 4 pieces)