Powerbuilt 647626 Brake Fluid Tester Brake Fluid Tester This Device Is for checking the quality of the Brake Fluid In the Reservoir and In the lines The Led Indicators will Identify the percentage of water content In the Brake Fluid Easy to use - simply power up, dip probes into brake fluid and read results LED lights indicate brake fluid quality Includes battery and protective cap Works with DOT 4 brake fluid