Nulon Lead Substitute Valve Saver makes unleaded petrol safe for use in all vehicles designed to run on leaded petrol. Lead Substitute uses the latest and safest potassium technology to provide unsurpassed valve and valve seat protection. Older engines with cast-iron cylinder heads can use Nulon Lead Substitute Valve Saver with unleaded petrol for an indefinite period of time to avoid costly cylinder head modifications. Lead Substitute Valve Saver provides maximum upper cylinder lubrication. It can also be used in vehicles running on unleaded petrol where additional upper cylinder lubrication is required. Nulon Lead Substitute Valve Saver is also the recommended refill for LPG under-bonnet lubrication reservoirs. Benefits Reduces valve seat burning & wear Helps lubricate top piston rings Prevents valve seat recession (VSR) Helps clean upper cylinder deposits Provides better valve sealing Cost-effective solution for classic car owners Helps dissipate high temperature from exhaust valves Safe for use with catalytic converters or oxygen sensors