This component is supplied by the original equipment manufacturer. It is specially made for use with Campbell Hausfeld spray gun. This is the top cover for the container. It provides an identical replacement for a faulty or a missing component that was included with a new unit. For the proper application please refer to the appropriate diagram of your model. This high-quality part is made of durable plastic material and is sold individually. Replacing it is a simple task that does not require any tools.