Filter Filters 88.4dB Remove All Filters Price $100-$500 (2) Condition New (2) Brand Harmony Audio (2) Size 18" (2) Voice Coils Dual (2) Harmony Audio HA-ML182 Monolith 18" Competition Sub 3500W Dual 2 Ohm Subwoofer $379.95 (2) Harmony Audio HA-ML181 Monolith 18" Competition Sub 3500W Dual 1 Ohm Subwoofer $379.95 (1)