This Berliss Bearing Company PS-3890 mechanical pump seal is designed to prevent fluid leakage around rotating shafts in various pump applications. It features a 5/8" shaft diameter and incorporates Buna (nitrile rubber) for elastomeric components and carbon graphite for the primary sealing face. Buna provides resistance to water, oils, and certain chemicals, while carbon graphite offers self-lubricating, low-friction, and wear-resistant properties, commonly mating with a ceramic stationary seat. Resin-impregnated carbon graphite is suitable for general duty in water, coolants, fuels, oils, and light chemical solutions. This seal is rated for temperatures from -45°C to 205°C (-49°F to 400°F) and pressures up to 75 psig, making it suitable for small centrifugal water pumps, jet pumps, and swimming pool pu