A back-to-back PTFE lip seal feature two distinct PTFE sealing elements oriented in opposite direction away from each other. The primary lips point in opposite directions to effectively separate two different media or simultaneously contain internal pressure while blocking external pressure. A back-to-back PTFE lip seal is useful when you need seal two different media on opposite sides, prevent fluid from moving from one side to the other, protect against contamination coming from either side. Each lip therefore creates a sealing barrier against pressure or fluid coming from its respective side