Lucas Oil Engine Break-In Oil Additive - TB Zinc Plus is designed for race applications requiring additional extreme pressure additives. It protects camshaft lifters and valve train during break-in period of motor and is excellent for flat tappet camshafts during break-in or as an additive to any motor oil to prevent premature wear. Dyno testing shows a more efficient break-in when used resulting in less engine run time prior to race day. Add one bottle with every oil change to increase the zinc content of your motor oil. Not designed for passenger car use.