Shaft seals are critical components in mechanical systems, designed to prevent leakage of fluids and contaminants while retaining lubricants. Commonly used in rotating machinery, these seals ensure smooth operation and prolong equipment lifespan. Key types include lip seals, mechanical seals, and labyrinth seals, each suited for specific applications like pumps, motors, and gearboxes. Materials range from rubber (Nitrile, Viton) to PTFE, offering resistance to heat, pressure, and chemicals. Features may include double-lipped designs for extra protection or spring-loaded mechanisms for consistent radial force. Examples: rotary shaft seals, hydraulic seals, and bearing isolators.