English: Figure 10. Nano containment hood adapted from a pharmaceutical balance enclosure. The use of bench-mounted weighing enclosures is common for the manipulation of small amounts of material. These fume hood-like local exhaust ventilation (LEV) devices typically operate at airflow rates lower than those in traditional fume hoods and use airfoils at enclosure sills to reduce turbulence and potential for leakage. They also have face velocity alarms to alert the user to potentially unsafe operating conditions. Based on the hazards assessment, these fume hood-like LEV devices can be outfitted with HEPA filtration or connected to the ventilation exhaust system.