In recent years in Australia and New Zealand, linseed oil has been incorporated in preservative formulations as a solvent and water repellent to "envelope treat" timber. This involves just treating the outer 5 mm of the cross-section of a timber member with preservative (e.g., permethrin 25:75), leaving the core untreated. While not as effective as CCA or LOSP methods, envelope treatments are significantly cheaper, as they use far less preservative. Major preservative manufacturers add a blue (or red) dye to envelope treatments. Blue colored timber is for use south of the Tropic of Capricorn and red for elsewhere. The colored dye also indicates that the timber is treated for resistance to termites/white ants. There is an ongoing promotional campaign in Australia for this type of treatment.