Ceiling Hangers shall consist of a side attachment steel angle gusseted on each side to prevent bending. The gussets shall protect an AASHTO Bridge Bearing Quality LDS Rubber Element molded with an integral lock in grommet at the bottom to prevent steel rod to housing acoustical short circuiting. Dynamic Stiffness shall not exceed 1.4 nor the corrected frequency 8 Hz. Housing configurations shall be offered for simple attachment to 11/2 x 1/2 channels or 12 gauge wire. Ceiling Hangers shall be Mason Industries HDSMCC or WHDSM. Submittals shall confirm AASHTO Quality and Dynamic Stiffness in addition to frequency.