The wheel cylinder cups, master cylinder primary cups, and master cylinder secondary cups are intended for use in wheel cylinders, master cylinders, and slave cylinders in hydraulic-brake systems of trucks and other heavy-duty automotive equipment where the cylinder cups are subjected to temperatures ranging from +248°F to -67° F (+120°C to - 55°C). Wheel cylinder cups, master cylinder primary cups, and master cylinder secondary cups that are intended for use for commercial hydraulic components are not designed to withstand these extreme conditions or sudden environmental changes, and could experience catastrophic failure.