Dirty air filters can cause decreased fuel mileage, increased engine wear, and even problems starting the engine. Check your engine air filter at every oil change and always replace a dirty filter with a high-quality Bosch Workshop engine air filter to restore protection, performance, and efficiency. Bosch Workshop Air Filters are constructed with a high number of pleats for a robust particle holding capacity and deliver 98% filtration efficiency in removing small particles from the incoming air to guard against engine wear. The high velocity cellulose cured media provides minimum air resistance and ensures even pleat distance for optimum efficiency. A high-quality polyurethane foam seal provides elasticity and sealing performance, while protecting against water and heat intrusion into the air intake system. All features combined ensure only the cleanest air for strong engine protection, high-performance and better fuel efficiency.