A T-nut, T nut, or tee nut (also known as a blind nut or insert nut) is a type of nut used to fasten a wood, particle board or other composite materials, leaving a flush surface.
Tee Nuts are comprised of a long thin body and a flange at one end, resembling a T in profile. The flanges of the T-nuts have hooks or serrations on the prongs that dig into a wooden work piece as the bolt is tightened from the opposite side of the piece, providing better retention.