Used to repair defective wood in and around doors, windows, wood gutters, columns, and more. This material expands and contracts as wood does, and can be used for interior and exterior applications. First, remove all defective wood and brush on Primatrate, a two-part primer (sold separately). Then mix and apply the two-part wood filler, which comes pre-measured in a single or double caulking tube. Double tube fills 24 cubic inches; single tube fills 8 cubic inches. Double tube requires double caulking gun (sold separately, or may be rented).