Refractometer for radiator coolant, battery acid and AdBlue

The refractometer is for testing radiator coolant, battery acid and the quality of AdBlue®. The tester indicates at a glance whether the fluid contains enough antifreeze. The scale indicates the temperature in °C down to which the fluid is protected against freezing. For testing battery acid, the acid concentration is displayed in kg/l. All pictures and videos are illustrative.