The Most Durable and Dependable Fluoroelastomer Tubing GORE® High Resilience Tubing Style 400 is a unique composite of expanded PTFE (ePTFE) and Viton® fluoroelastomer (FKM) that enables superior cost effectiven......The Most Durable and Dependable Fluoroelastomer Tubing GORE® High Resilience Tubing Style 400 is a unique composite of expanded PTFE (ePTFE) and Viton® fluoroelastomer (FKM) that enables superior cost effectiveness in peristaltic pumping processes.