Our push-in F-1 Airbrush Paint Cup (1/4 Oz ) is ideal for doing detail work, using small amounts of paint or mixing colors with a paint brush on the fly. Using the cup makes clean up easier, you can run it under the sink and/or pour water right into it for cleaning. If you are using a compressor with less than adequate pressure (using the bottle adaptors with a full bottle usually requires 40-60lbs) this can be used at 30-35 lbs and by turning down the pressure you can get finer detail lines and more control. Not included in F-1 Airbrush Set. TIP: You can also reverse the Air Diffuser (Cone tIp of airbrush) for finer lines.