These Titan brake fluid testers can quickly and easily check the percentage of moisture in the brake fluid or hydraulic clutch fluid. These handy pocket-sized testers feature red, yellow, and green indicator lights for easy readings. Green signifies that moisture is less than 1.5 percent and is OK. Yellow indicates that moisture is present between 1.5 percent and 3.0 percent and that flushing the fluid should be considered. Red indicates that moisture is greater than 3.0 percent and that the fluid should be flushed immediately.