Feature: 100% brand new and high qualityGreat Brake Fluid Tester LED Car Vehicle Auto Automotive Testing ToolColor: BlackSize: Approx. 15cm/5.9"Power Supply: 1 x 1.5V "AAA" Battery (Battery Included)Principle: according to conductivity changes to determine moisture change in brake fluid， with five different color LED indicatorHow to use:Unscrew the brake fluid reservoir， and pull of the cap of the brake fluid tester. Dip the test probes into the brake fluid up to the plastic rim of the device.Indicator Description:5 LEDs indicating the water % in the brake fluid:Green: Battery OK， i.e.: No water contained in the brake fluid.Yellow: Less than 1% of water content in brake fluid.Yellow/yellow: Approx.2% of water content in brake fluid.Yellow/ yellow / red: Approx. 3% of water content in brake fluid. The brake fluid should be changed.Yellow/yellow/red/red: At least 4% of water content in brake fluid. The brake fluid must be changed urgently! Extreme danger!Attention:Replace battery if the Green LED not light up any loger after you press power on button. Wash the test probe with tap water after every use.In case of skin contact with brake fluid， thoroughly wash the affected skin or clothing with water.Do not expose brake fluid to the atmosphere for a long time as the fluid is hightly hygroscopic!Note: Due to the difference between different monitors， the picture may not reflect the actual color of the item. Thanks for your understanding.Packing list:1 x Brake Fluid Teste 1 x 1.5V "AAA" Battery