DOUBLE PROTECTION: One-piece tire valve stem cover features illuminated plastic inserts and clear housing protection to prevent valve stem corrosion. A good valve cover will prolong the life of the tire. LUMINOUS DESIGN: The inner layer of the valve stem cover is designed with luminous material, which can make the car decorated with Tire Valve Stem Caps lights at night. When your wheel starts to move, it automatically flashes and creates a circle of light that makes your car/motorcycle/bike look beautiful. WIDE APPLICATION: tire valve stem cover with inner diameter of 7mm and inner height of 13.8mm can be suitable for cars, bicycles, SUVs, trucks, bicycles and motor vehicles, etc. EASY INSTALLATION: Glow tire valve stem cap inner protection features a swivel thread design for easy hand tightening during installation. NOTE: Since the fluorescent material needs to absorb the light source, it glows at night. Stem cpas do not absorb light sources when stored in airtight packaging for extended periods of time. Illuminate with LEDs or place them in sunlight for 5-15 seconds before using fluorescent stem cpas for the first time.