The 8024204025 is typically rated for a maximum surge pressure of 20" WC to protect the internal diaphragm from damage

and industrial lighting applications

the 8023204130 is specifically designed for air differential pressure and should only be used in air or non-combustible gas applications

The 9J is a solid one-piece sleeve requiring equipment separation for installation

electric heaters

Lau 60556501 Fan Blade 319852-301 The 8024204025 is typically ratedThe Lau 60556501 Fan Blade is a robust, professional grade 18 inch condenser style fan blade engineered for demanding HVACR applications. Built for high efficiency thermal transfer, this unit features a 33 degree pitch and a 3 blade configuration, optimized for maximum airflow in outdoor condensing units. Constructed with high strength aluminum and a corrosion resistant center spider, it provides long term structural integrity in harsh environments.