Which appliance is best described as a device with an inlet and an outlet plus an extra smaller outlet?

The water thief appliance is designed specifically to draw water from a larger diameter supply line while allowing the continued flow of water through the main line. This appliance typically features one inlet connected to the larger supply line and one or more outlets, with one of those outlets being smaller than the inlet. This smaller outlet can be used to supply water to a secondary line or a hose, which is often necessary in firefighting scenarios where multiple lines need to be supplied from a single source. The ability to maintain water flow through the main line while also providing access to a secondary line makes the water thief a versatile tool in firefighting operations, allowing for efficient water management.

In contrast, the Siamese appliance typically combines two hose lines into one, but it does not have an extra smaller outlet. The Wye appliance splits a single supply line into two lines, but again, it does not include an additional smaller outlet. A coupling device simply connects two hoses together and does not have the functionality of an inlet and multiple outlets. Each of these options serves important roles in firefighting, but the water thief appliance is unique in its design, allowing for simultaneous supply to multiple hoses from a single source.