JMP refractometer / antifreeze tester Refractometer for radiator antifreeze (coolant additives), windshield wiper water, battery acid density and equipment AdBlue Proven workshop tester with which it can be determined whether the cooling water (scale C) or windscreen wiper water (scale D) contains sufficient antifreeze A light / dark dividing line (1) on different scales indicates up to what temperature in ° C the liquid is protected against frost In the case of battery acid, the acid density is displayed in kg / l (scale A) Assessment of the quality of equipment AdBlue® (scale B)