Cuprinol Ultimate Garden Wood Preserver can be used on all types of rough or planed wood such as sheds, fences, summerhouses, gates and arbours. Its formulated to work in 3 ways, firstly UV filters give long lasting colours for up to 5 years. Added waxes & resins provide advanced weather protection along with added active ingredients that penetrate deep into the wood top protect against rot, decay and blue stain.