The Ultra Compact Oil Tank Filter Kit is designed for bottom outlet domestic heating oil tanks to remove debris with instant isolation and no pollution risk. A hydraulic filter is a component used by hydraulic systems to continuously remove contaminants in the hydraulic oil. This process will purify the hydraulic fluid and protect the system from damages created by the particle contents. The primary purpose of hydraulic suction filters is to trap and remove impurities from the hydraulic fluid. Hydraulic strainer filter can actually do more harm than good. And so their inclusion in a hydraulic system is misguided.