What fitting is needed to connect the 3 1/2" hose to a 3" inlet on the rig?

To connect a 3 1/2" hose to a 3" inlet on the rig, the appropriate fitting to use is a 3" double male fitting.

This fitting has two male threads, which allows it to connect a hose with a larger diameter (the 3 1/2") to an inlet with a smaller diameter (3"). The 3" double male fitting provides a secure and tight connection between the two hoses, ensuring that water can flow effectively from the inlet to the larger hose without any leaks or issues.

Using a 3" double male fitting is essential in firefighting operations, as reliable connections are critical to maintain water supply and pressure. This choice helps to maximize flow capacity and ensures compatibility with the fire apparatus' intake systems. Other fittings, like a 3" single male or fittings of different sizes, would not provide the necessary connection or compatibility needed in this situation.