18" Harmony Audio HA-ML181 Monolith 18" Competition Sub 3500W Dual 1 Ohm Subwoofer $379.95 (1) Harmony Audio HA-ML182 Monolith 18" Competition Sub 3500W Dual 2 Ohm Subwoofer $379.95 (2) Harmony HA-ML1X18D2 18" Dual 2-OHM Subwoofer Vented Enclosure Box Subpackage $549.95 2x Harmony HA-ML181 Monolith 18" Competition SPL Sub 3500W Dual 1 Ohm Subwoofer $724.99 2x Harmony HA-ML182 Monolith 18" Competition SPL Sub 3500W Dual 2 Ohm Subwoofer $724.99 Harmony Audio HA-ML181 Competition SPL 18" Sub Subwoofer Bundle with... $560.99 4x Harmony HA-ML181 Monolith 18" Competition SPL Sub 3500W Dual 1 Ohm Subwoofer $1420.99 4x Harmony HA-ML182 Monolith 18" Competition SPL Sub 3500W Dual 2 Ohm Subwoofer $1420.99 2x Harmony Audio HA-ML181 Competition SPL 18" Sub Subwoofer & CXA1800.1 Amp $1079.99 2x Harmony Audio HA-ML182 Competition SPL 18" Sub Subwoofer & CXA1800.1 Amp $1029.99 Harmony Audio HA-ML181 Competition SPL 18" Sub Subwoofer Bundle with Kicker... $599.99 Harmony Audio HA-ML182 Competition SPL 18" Sub Subwoofer & CXA1200.1 Amp Package $669.99