Aluminum inline water temperature sensor adapters (also called joint pipes). They allow you to mount an aftermarket coolant temperature sensor or digital gauge sensor directly inside your vehicle's radiator hose.Overview & SpecsBrand: EPMAN Racing Parts Italy.Function: Spliced directly into the upper or lower radiator hose to measure real-time coolant temperatures, helping prevent engine overheating.Port Size: Features a standard 1/8" NPT threaded hole on the block side to screw in the temperature sender unit.Sizes Present: The image shows a variety of common outside diameters to fit different vehicles: 28mm, 34mm, 38mm, 40mm, and 42mm