We recommend using the [Hardwood Formula Penetrating Oil Finish](https://www.diyhomecenter.com/penofin-exotic-hardwood-formula-exterior-penetrating-oil-finish-1-gallon) for your cumaru deck. Since it is new, we also recommend using the [First Step Prep for Hardwood](https://www.diyhomecenter.com/penofin-first-step-prep-hardwoods-cleaner), as it will prepare new hardwood for finishing, remove any mill glaze, and open the pores on the wood's surface for better penetration.