The Donaldson P635903 is a high-quality safety air filter designed to provide crucial secondary filtration for engines in demanding heavy-duty applications. This genuine Donaldson filter features a durable cellulose media, ensuring high efficiency in capturing fine particulates and protecting the engine from contaminants. It functions as an inner filter, complementing the primary air filter to extend engine life and maintain peak performance. Key technical specifications include an outer diameter of 101.6 mm, an inner diameter of 76.2 mm, and an overall length of 279.4 mm.