What does the last clause of this sentence mean? it should be easy to your native speakers?

Looking at context - a href="http://www.wipo.int/pctdb/fr/wo.jsp?WO=2007062474&IA=US2009030136&DISPLAY=DESC" rel="nofollow"http://www.wipo.int/pctdb/fr/wo.jsp?WO=2…/a - it means a portion of the end wall comprises a hard surface material.