LC1 MSK metal ceiling kit lc1-mfd metal flameproof cover is easy to install single speaker and speaker/flameproof cover combination. The flameproof cover is fixed to the ceiling before the ceiling speakers are installed. It has a double joint inlet for loop cabling and installation of optional safety wire rope. The connection is made through the innovative ceramic screw terminal junction box and loop device on the metal flameproof cover. Suitable for air treatment.