This is a dust cyclone. This one has the brand name Dust Deputy. MDF makes lots of really fine dust that clogs my shop vac filter quickly. This device traps 99% of the dust before it gets to the filter.
To collect the dust, you have to remember to turn the vacuum on each time. With this device, you plug in the vacuum and the power tool you are using. When you start your saw or whatever the vac starts automatically and when you turn the saw off the vac runs for 7 seconds more to clear the hose and then automatically shuts off.








