Have a vacuum that spews dust out the exhaust? Turn it into a dustless vacuum with this bag. The Dustless Technology WunderBag 4-7 Gallon Wet Dry Vac Dust Collection Filter Bags (D1340) fit most major 4-7 gallon major brand shop-type vacuums. 

Providing superior filtration, these Dustless Technologies micro pre-filter bags capture 99.97% of particles at 0.5 microns. That is 0.00005 centimeters across, much smaller than most dust particles. Although this bag is not HEPA rated, it can make any vacuum have superior filtration.