How it’s green: You can improve your gas mileage by up to 3.3 percent by keeping your tires inflated to the proper pressure. The EPA says under-inflated tires can lower gas mileage by 0.3 percent for every 1 psi drop in pressure of all four tires. And properly inflated tires are safer and last longer.
Manufacturer’s description: The Gas Saver Valve Cap visually indicates when your vehicle’s tire pressure is low. The green indicator inside the cap disappears at 27psi, showing a low pressure condition. Gas Saver Valve Caps will work in conjunction with many vehicles equipped with on-board tire pressure monitoring systems.
Available at: Walmart