1. This product is for monitoring tire pressure: if the pressure of tire is 10% less than required, the tire pressure indicator will show red, otherwise it will show normal which is green. Each monitor is calibrated to the specified PSI, if your tire is under inflated, it will not show green. For example, if your recommended tire pressure is 40psi, then you should purchase our PSI 40 monitor caps. If your current tire pressure is under-inflated, when you install our monitor cap onto your tire, the cap will not show full green. (It doesn’t check your tire over inflated) 2. Chrome Plated Brass 3. Patented, designed, assembled and tested in the USA. 4. The monitors are available in chrome (plated brass valve body) to complement any wheel and fits passenger vehicles, SUV’s, trucks, trailers, motorcycles, ATV’s, RV’s, commercial vehicles, and bicycles. 5. After installation, please drive 10 miles or more to activate the monitors. 6. Motorcycles and bicycles: Please check for proper clearance between monitor and brake system.