Windshield washer bottle cap (wiper fluid reservoir cap / wiper radiator cap) What it does Prevents stains, dirt and debris from entering the washer fluid tank so the car's reservoir and internal components are less prone to damage. Keeps rain and moisture out of the wiper fluid bottle to protect internal parts and maintain reliable operation in humid or wet climates. Provides a tight, leakresistant seal that withstands weather exposure and reduces the risk of cracks or breakage over time. Key benefits Protection: Stops contaminants and water intrusion that can clog pumps or corrode internal parts. Durability: Made from automotivegrade plastic for stable, longlasting use; easy to carry and install. Reliable sealing: Builtin gasket provides waterproofing — carefully check that the cover is seated and sealed with the gasket for performance. Precision fit: Engineered for a secure installation to reduce movement, stress, and eventual failure. Material and performance Material: quality automotive plastic selected for stability and resistance to environmental stress. Sealing: Gasketequipped cap designed to prevent leaks and keep the reservoir dry in rain and humid conditions. Durability: Designed to endure regular vehicle use and harsh weather without cracking or degrading quickly. Use scenarios Routine maintenance: a worn or missing washer bottle cap during regular service to prevent pump damage and contamination. Outdoor parking: Protect the washer fluid tank and internal components when the car is parked outside in rain or humid environments. Offroad or dusty driving: Keep dust, grit and road debris out of the fluid reservoir during dirtroad or constructionzone travel. Installation note When installing, carefully check that the cover is fully seated and the gasket forms a complete seal to ensure waterproofing and leak resistance.