Hydraulic seals and pneumatic seals include piston seals, rod seals, U-cups, vee, cup, W, piston, and flange packings. Hydraulic seals and pneumatic seals are designed for the reciprocating motion that is common in hydraulic and pneumatic applications, such as cylinders.  Hydraulic seals are designed for high-pressure dynamic applications such as hydraulic cylinders. Pneumatic seals are used in pneumatic cylinders and valves and generally are designed for lower operating pressures than hydraulic seals. Pneumatic applications also typically demand higher operating speeds and lower friction seals than hydraulic applications.  These seals may be used for rotary and reciprocating motion.  Some hydraulic seals and pneumatic seals are composite. Composite seals are two- or multi-part seals manufactured as an integral unit. A typical composite seal consists of an integral PTFE ring and elastomer ring, providing the properties of an elastomeric ring with a rigid, low friction (PTFE) working face. These seals can have a variety of different cross sections. Some forms of composite seals are also referred to as polyseals, wedge-action seals, crown seals and tri-seals (3 part seals).