This is the PERRIN Coolant Hose Adapter which allows users to have a safe provision to install an aftermarket water temperature gauge. This is a 38mm adapter which has been designed to sit between one of your preferred coolant hoses. Installation would require you to cut your hose and slip each end onto the adapter where the provided worm clamps will secure the hose down. This adapter will have a 1/8 NPT provision to host your aftermarket water temp gauge sensor.
It will come in an anodized black finish for extra protection against corrosion, and to provide a clean look to your engine bay.