Vallejo Model Air Underside Blue (AV71332) Water-based matt acrylic engineered for airbrush use. The Model Air range features an extensive catalog of military colors from WWI, WWII, and modern eras, developed through expert historical analysis to provide accurate period references. Use undiluted or thin with Vallejo Airbrush Thinner or Flow Improver. Prime the substrate first, then apply in successive coats. Colors set quickly and form a tough, even coating without obscuring fine details. Recommended compressor setting: 15–20 PSI (0.5–1 kg). Brushable as well as sprayable. 17ml bottle. Safe, non-flammable, contains no solvents. Maintain airbrushes with Vallejo Airbrush Cleaner.