Lau 60556101 is a heavy-duty 18-inch 3-blade aluminum condenser fan blade designed to move air efficiently across coils in rooftop air conditioners, heat exchangers, and other commercial or industrial HVAC equipment.  Made of high-strength aluminum with a corrosion-resistant center spider, this propeller-style blade has a 27° pitch, clockwise (CW) rotation, and a maximum rating of 1140 RPM to deliver reliable airflow and heat transfer in ambient-air HVAC systems.  It uses an interchangeable hub (sold separately, such as 05214101 and 05380401) compatible with common motor shaft bores including 1/4", 5/16", 3/8", 1/2", 5/8", and 3/4" to simplify replacement and match a wide range of HVAC condenser motors.