Hydrometer for testing the charge of a car battery. The height of the float shows the state of charge of the battery indicated by Red/White/Green Stock Photo - Alamy
Battery Hydrometer | Camping World
Battery Hydrometer | Camping World
Battery Hydrometer | West Marine
Hydrometer | Automotive Terminology Explained
Amazon.com: Deka Temperature Correcting Battery Hydrometer (00231) : Automotive
Battery hydrometer hi-res stock photography and images - Alamy