The Donaldson 4.21" Spin-On Coolant Filter is designed to provide superior protection from contaminants in your coolant system. This filter is constructed with seals specifically designed to withstand extreme temperatures. Furthermore, this coolant filter contains enough additive to initially charge the cooling system to reach the first service interval. The rugged design and materials used in this filter ensure extra durability and reliability. With a range of filtration methods available, you can choose the one that best suits your maintenance practices and schedules. FleetPride is your First Click in Heavy Duty®.