The basics Iwata Big Mouth Airbrush Bottle 1 oz / 30 ml Cylinder with 20 mm adaptor cap is solvent-proof. The benefits The domed, high-strength one piece cap with offset friction fit connector easily affixes onto your airbrush. The uses For all airbrush paint mediums. The bottom line It's raised air intake creates a splash-proof opening. The detachable pick up tube makes this an easy to clean cap.