SKF Timing Belt Tensioner Pulleys maintain constant belt tension ensuring reliable and efficient engine operation. All SKF Tensioner Pulleys are manufactured with low friction ball bearings and high performance grease and seal. For more than 100 years, the world's engineers, technicians and mechanics have turned to SKF for the best possible solutions. Available for a wide range of applications and needs, SKF bearings and seals are designed and manufactured to the highest quality standards, ensuring long life and safety.