Yamaha Superior Valve Oils are based on a newly developed synthetic formula. The Superior Valve Oil synthetic formula is more consistent than mineral based oils and provides superior performance in all playing environments. The advanced formula is produced using a consistent molecule size. Standard valve oils contain mineral oil which is made up of molecules varying in size. The varied molecule make-up of mineral oil allows the oil to evaporate at an uneven rate, leaving high viscosity particles behind. The even molecules found in the new Yamaha Superior Valve Oil synthetic formula allow the oil to evaporate smoothly, guaranteeing a longer life and extremely responsive action.