surface :  A.    flat and tidy

                B.    no defects

                C.   no spots

chemical property:   A. against resistance

                                B.  radiation resistance

                                C.  low permeability

                                D.  high pressure

                                E.  oil resistance

                                F.  anti-corrosin

Usage:       A.   electrical insulation parts 

                  B.   connector accessaries

                  C.   corrosive fluid conduit