KEF CI200QSB-THX Ultra Thin Bezel 8'' Wall Subwoofer - PairTHX ULTRA Certified 200mm Subwoofer Certified to THX ULTRA2 and THX SELECT2 standards, the formidable Ci200QSb THX in wall subwoofer delivers deep bass and theatre thumping output capabilities, matched to the uncanny ability to deliver all the drama and emotional intensity of full theatre sound quality. Ci200QSb THX Certified to THX ULTRA2 and THX SELECT2 standards, the formidable Ci200QSb THX in wall subwoofer delivers deep bass and theatre thumping