We offer two NHOU products and they both protect exceptionally well.
The NH Oil Undercoating is for used vehicles with existing rust and is an annual coating but is also an option for brand new vehicles. It is an oil so it does not completely dry but it does congeal. Underbody washes are not recommended when the oil undercoating is applied.
The NHOU Boss Wax N' Oil is for brand new vehicles that are completely rust free. This is a more permanent solution that is applied once and comes with a transferable life time warranty and then touchups are required every other year to oil the internal cavities. The wax is a cleaner look vs the oil.