[silver]

We are very important to customer experience and if you have any questions after you receive the product,please contact us!
A. The surface of the protective film is dyed by cutting down attenuation or fluid (or other conductive particles).
Process: Wipe the ruler surface protective film with a dry cloth dampened with slightly waterless ethanol or aviation gasoline. Quietly (if not, liquid will cause other problems to enter electronic components, but be careful not to drip too much! ) Twist small drops of anhydrous ethanol or aviation gasoline

B. Copper clad plate under protective membrane is corroded and affected by blackening
Therapeutic method: discovery, protective film, polish the surface of copper strips with high-grade rubber or metal tissue sandpaper to clean it.

C, Battery is not sufficient - Treatment: Replace a new battery.

In this case you will not be able to open any conflicts.