The Baldwin 5-3/8" Spin-On Coolant Filter is designed to help keep your engine running smoothly and prolong its life. This spin-on filter is easy to install and replace. The filter has an outside diameter of 3-11/16". To ensure that your cooling system is functioning properly, the filter comes with a Fleetstrip coolant test kit, which provides a convenient and reliable way to assess the status of your cooling system. With this filter, you can be sure that your engine is running at its best. FleetPride is your First Click in Heavy Duty®.