The front grille is required for the four way ceiling cassette units. This grille will fit LCN series units. The LCN ceiling cassettes are used with the LG Single Zone Systems.
The PT-UMC1B is a black grille. It is about 24" x 24" and covers the inner working of the ceiling cassette unit as well as the ceiling cut-out. Air flow is directed through the grille cover.
It is not for use with the LCN097HV4 or the LCN127HV4 Ceiling Units.