Fram TG3614 Tough Guard Passenger Car Spin-On Oil Filter (Pack of 2) Extreme Engine Protection Combination synthetic glass and cellulose media formulated for top-rated efficiency for the life of the filter Silicone anti-drainback valve allows filter to retain oil when engine is off and benefit from a full oil filter at start up Screen-over by-pass valve provides backup filtration during cold start-ups and added protection against larger particles of dirt. Screen-over feature available only on models with a by-pass valve Do You Drive Tough?