Balancer/Pulley Assembly: Balancer, Woodruff Key, Instruction Sheet. (Serpentine Belt); 7.5625in. Diameter. Durable and sleek, Dorman Harmonic Balancers feature a stress-resistant rubber bond that withstands the damaging effects of heat, salt, ozone and general wear and tear. The ductile steel construction allows for improved tensile and impact strength, safeguarding the engine and maintaining fuel efficiency year after year. Dorman Harmonic Balancers undergo detailed dimensional checks of the full assembly and critical components to ensure the strength and integrity of the part.