tk-250 speaker

[N3CHU]

Hi All, would anyone have the part number(and name) of the little cloth filter that is held down by three small screws in front of the tk-250/350 speaker. In time some warp inward towards the speaker and touch it causing a wird sound.Dont know if the screen is part or the metel cover or just a screen and a couple of gaskets. It is effective for keeping rust and small pieces of debris from getting to the speaker drawn in by the magnet in the speaker. any help is appreciated. Davie n_3_c_h_u at atlanticbb dot net