radial shaft seals also known as radial shaft sealing rings, radial shaft seals, simmering, lip seal, simmerink, shaft washers and oil rings are sealing elements designed for the sealing of rotating shafts and other parts of machines. Shaft GUFERO® sealing ring is reinforced with a metal ring and equipped with a tensioning spring. In some types, however, an oil seal without a spring or metal ring is used.