When discussing oil seals, several factors come into play. First and foremost is the material used in the seal's construction. Common materials include rubber, polyurethane, and fluorocarbon, each having its own advantages and disadvantages. For instance, rubber seals are generally cost-effective and can work well under moderate conditions, while fluorocarbon seals are exceptionally resistant to heat and chemicals, making them ideal for high-performance applications.

The design of the lip is crucial; its profile allows it to make optimal contact with the shaft, creating a seal that can accommodate the shaft's rotation. Some rotary lip seals also include a dust lip or exclusion barrier, which helps protect the primary sealing lip from contaminants such as dirt and debris.