POWERTEC 4 in. 90-Degree Elbow Right Angle Dust Collector Connector, ABS Plastic (2-Pack) 70105-P2 - The Home Depot
Dust Gorilla Pro 5hp VFD HEPA-GFM Cyclone Dust Collector with SMART Boost (230V, 1-phase, 55-Gallon Wall-Mounted) | Oneida Air Systems
Amazon.com: Dust Collection Fittings Cone Reducer 4" to 2 1/2" in & 4" inch splice/coupler with 4 Vacuum Hose Adapters 2 1/2" in to 1" in plus Shop Vac Adapter 2 1/2"
2-1/2" Dust Collection Starter Kit | Rockler Woodworking and Hardware