Content Container Discharge Sound Attenuators for Model Series 3000 and 30X are available with a variety of liners. Models Attenuator AT303 - 3 Foot Long AT305 - 5 Foot Long MOA303 - Multi-Outlet • 3 Foot Long MOA305 - Multi-Outlet • 5 Foot Long Submittals All Submittals Combined Options and Accessories AT303, AT305 • Discharge Sound Attenuators for Single Duct Terminal Units Liner Option • Fiberglass Dual Density MOA303,MOA305 Multi-Outlet Attenuator for Single Duct Terminal Units