The unit is plastic and the big problem with it is the iron mount area has two internal grip edges that are meant to grip the iron as you slot it in.  Problem is those protrusions are not flexible but hard plastic so that if you iron isn't that exact size it won't fit at all and the holder becomes useless.  This was the case with both of my irons, neither would fit.  Great idea terrible design.  Modern steam irons won't fit as their bases are too wide.