English: Figure 15. Powder-handling enclosure. For a number of years, equipment manufacturers have offered ventilated enclosures specifically for weighing and manipulating small quantities of dry powders. These were first developed and marketed to the pharmaceutical industry, but they are now sold as general purpose powder-handling enclosures. Systems can be self-contained, with their own fan and HEPA filtration unit, or connected to a central exhaust system. The exhaust can be ducted to the outside or recirculated into the room. One advantage of these devices is that they operate at much lower flow rates and velocities than the chemical hoods. The internal turbulence is reduced significantly, lessening the potential for loss or ejection of the nanomaterial.