ActronAir Discharge Muffler 1/2" Solder Steel (Heavy Duty) is a heavy-duty discharge muffler for high-load ActronAir split ducted system applications, providing greater attenuation of compressor discharge pulsation than the standard 1/2 inch variants for systems where noise reduction is critical. Confirm the correct muffler variant against the system service documentation -- 4590-001, 4590-021, and 4590-025 are dimensionally similar but suited to different system applications. Isolate power and recover all refrigerant before replacing any discharge line components.