Wipers are primarily designed to stop contaminants from entering a cylinder on the rod; however, they can also act as a secondary rod seal. If contaminants were allowed to enter the cylinder it could lead to damage of your rod and/or the damage of other sealing components. A properly selected wiper could help reduce the need for unscheduled maintenance and even increase the time between maintenance cycles.
It is important to determine the correct style and material for your application. Tings that should be considered when selecting the material of your wiper include: required abrasion resistance, elasticity, resilience and fluid compatibility.