If you’ve already looked at the 42x11mm board, don’t assume this is much the same. The face is still 42mm wide, but the extra thickness changes how the timber sits once it’s fitted. At 18mm deep, it feels more substantial around an opening or against another piece of trim. The face itself hasn’t been dressed up with grooves or shaped details. It’s simply a clean piece of pine for jobs where these dimensions work. Replacing an existing trim? Check the depth as well as the width. It’s an easy measurement to miss, and usually the one you notice when two pieces don’t line up.
