Introducing the Router Table Dust Collection System Set with 4 in. to 2-1/2 in. Reducer by POWERTEC. Finally, a dust collector kit that allows you to get the sawdust, woodchips, and debris from the top and bottom of your router, regardless of the type of cuts you're making. This complete dust collection fittings and accessories kit delivers the most comprehensive, cost-effective, and efficient system for keeping a clean, dust-free workshop and woodworking area. Features: Collects 85% of all saw dust from the router, Simultaneously collects top and bottom router plate dust, Switch router bits without removing the dust collector, Attaches to workshop vacs & dust collection systems, Quick and simple installation. As configured this dust collection kit connects to your dust collection system using a 2-1/2 in. ID flexible dust collection hose and a 2-1/2 in. hose clamp (not included). To connect to a shop vac the following POWERTEC components are recommended (sold separately): 70191 - 2-1/2 in. to 2-1/4 in. Screw end quick coupler 70198 - 2-1/2 in. Flexible dust collection hose 70127 - 2-1/2 in. Key hose clamp. Additional adapters or fittings may be required to connect to your shop vac or dust collector.