What is the difference between the Osmo UV Protection Oil (410) and Osmo UV Protection Oil Extra (420)?

While both products provide a clear, satin finish with very low V.O.C content and are made from a unique combination of natural oils and waxes, the main difference between the Osmo UV Protection Oil (410) and Osmo UV Protection Oil Extra (420) is that the 420 contains fungicides and biocides to protect against mould, algae and fungal growth. For this reason, the 410, which doesn't contain fungicides and biocides, can be used on interior and exterior wood surfaces whereas the 420 is just for exterior use.