The E-Z Red S104 Windshield Washer Hydrometer allows users to check the specific gravity for freeze-point temperatures of Methanol-based windshield washer fluids accurate to within +/- 3 degrees. This hydrometer offers a 32 degree F to -60 degree F range of direct, accurate temperature readings. The S104 has temperature scales in Fahrenheit and Celsius. It is unbreakable and easy-to-read, according to the company.
