This Internal Door Casing Frame Set is designed for fitting a door frame within an internal doorway, ready for hanging a suitable internal door. The casing has a finished section size of 33 x 108mm, corresponding to nominal dimensions of 38 x 113mm. The wider 108mm section provides an alternative to narrower door casings, helping you select a frame suited to the depth of the wall opening. Suitable for internal joinery work, renovations and new door installations, the casing can be cut and fitted to the required opening, subject to the dimensions of the supplied set.