PROAQUA VM8531BI00 is a special White Waterborne Primer for use on tannin-rich or extractive-rich substrates like oak and larch and is formulated to control the 'bleeding out' of extractives that may discolour the finishes. It is particularly suitable for conifer and broadleaf timbers and does not need an anti-tannin primer. It is a high build Primer with good thixotropy to avoid sags and runs.