The counterweight on a harmonic balancer is a key component of the rotating assembly. PRW nodular iron and/or Pro Series SFI-Rated harmonic balancers are manufactured to OEM balance and/or imbalance crankshaft specifications. Except when noted, counterweights may be removed to suit future upgrades to minimize machine shop engine balancing modifications. Proper balance reduces vibrations, prevents undue crankshaft and other engine components stress for prolonged engine life.