Lc1-cmr and lc1-cbb ceiling mounting ring and bottom box installation lc1-csmb surface mounting box this ABS surface mounting box is used to attach ceiling speakers to walls or hard ceilings. The side of the surface mounting box has two symmetrical opening holes (initial closing), followed by four mounting holes. To perform optional single point lifting for ceiling speakers and surface mounting box devices, Bosch also provides a separate LC1‑MSK metal ceiling kit.