Bosch BOVA-60HN1-M18M - 4 Ton/18.5 SEER Or 5 Ton/17.5 SEER Inverter Heat Pump Condenser, 208-230/1/60, R410a Refrigerant The direct-drive fan blades provide vortex suppression to reduce sound of airflow exiting the condensing section, thereby retaining relatively low noise at high speed - with sound levels as low as 56 dB.