Measure three dimensions with calipers: the shaft inner diameter (ID), the housing bore outer diameter (OD), and the housing depth (height). For example, a 20*35*7mm seal has a 20mm ID (≈0.79"), 35mm OD (≈1.38"), and 7mm height (≈0.28"). All three must match your application. When in doubt, measure the old seal directly.

"TC" indicates a double-lip seal design — a spring-loaded primary lip to retain lubricant plus a secondary dust lip to exclude contaminants. "FB" refers to the skeleton construction style: a fully encased metal ring that maintains the seal's shape and provides a rigid press-fit OD. This is the most common type used in gearboxes, pumps, and motors.

NBR TC oil seals are generally rated for shaft surface speeds up to approximately 4–6 m/s under normal lubricated conditions. Actual limits depend on shaft surface finish (Ra 0.2–0.8 µm recommended), operating temperature, and lubrication. For high-speed applications, verify against your equipment's OEM specifications.

NBR rubber offers good resistance to petroleum-based oils, water, and mild chemicals. The secondary dust lip provides additional protection against moisture and contaminants entering from outside. However, NBR is generally not recommended for prolonged exposure to ozone, strong acids, or ketone-based fluids. For harsh outdoor or chemical environments, FKM (Viton) seals may be more appropriate.

NBR (nitrile rubber) typically performs reliably in a continuous temperature range of approximately -40°F to +250°F (-40°C to +120°C). Short-term peaks may be tolerated, but sustained high temperatures accelerate rubber degradation. For applications above +120°C, consider FKM alternatives.

Yes. All sizes listed use metric dimensions (mm) and are compatible with standard metric shafts. The ID range covered is 20–28mm, with OD options from 28mm up to 62mm depending on the variant selected. These dimensions follow common DIN/ISO metric seal standards used in European and Asian machinery.

These seals are generally used in gearboxes, hydraulic pumps, electric motors, agricultural equipment (tractors, tillers), automotive differentials, industrial gearboxes, and any rotating shaft application where fluid retention and dust exclusion are required. They are a direct replacement for TC-type seals in the 20–28mm ID range.