Freudenberg Sealing Technologies Simrit 72 NBR 902 Seal, 4mm ID, 12mm OD, 6mm

Simmering Rotating shaft seals are a high performance oil seal delivering exceptional wear resistance and performance to a variety of functions including aerospace, railway, power transmission, automotive, machine tools, fluid handling, production line, energy and power generation.
With an elastomer outer casing manufactured from NBR 902 nitrile rubber and spring loaded sealing lip they can be used with mineral & synthetic oils and greases. Simmering radial seals offer significant improvements in seal wear and heat and friction generation, reducing power loss and lowering running costs as well as improving working life so improving costly downtime due to seal repairs.
Suitable replacement for R21 and in some instances R4 seals (please review manufacturers data sheet) Suitable for a comprehensive range of applications including axles, power tools, industrial gearboxes, motors and pumps.

Shaft tolerance ISO h11
Housing bore tolerance H8
90% Less friction torque
80% Less specific heat generation
50% Less wear
Pressure stable up to 0.5 bar
Suitable for bidirectional rotating shafts up to a velocity of 40 m/s