Mercury - Inline Oil Filter OptiMax Series Composite Filter Media 875284T01. Overview. Out on the water, you learn quickly that small parts often carry big responsibilities. The inline oil filter is one of those quiet heroes - you don't really think about it until it stops doing its job. When it's working right, everything feels smoother. Your OptiMax responds without hesitation, the throttle feels connected, and the engine holds that steady hum you've come to trust. The Quicksilver 875284T01 In