Nilfisk Aero 21 Hepa - Contractor-Grade Wet/Dry Hepa VacuumNilfisk Alto Aero 21 Hepa Contractor Grade Wet Dry Hepa Vacuum Nilfisk ALTO Aero 21 HEPA Contractor Grade Wet Dry HEPA Vacuum Aero 21 HEPA is a 20 liter (5. 2 gallon) contractor grade wet dry vacuum that features durable construction, low noise level, and Push & Clean semi automatic filter cleaning. Aero 21 HEPA includes a certified HEPA filter, built in storage for hose and accessories, exhaust blow function, and comes with full accessory kit and