Quick-Fit-Ceiling-Speaker-RVFM-Quick-Fit-Ceiling-Speaker-25 Hz-to-18k Hz-Frequency-Response-90d B-Sound-Pressure-Level-188mm-Diameter-Allows-the-Speaker-to-be-Pushed-into-the-Fitting-Position-in-one-Easy-Move-Spring-Loaded-Fixing-Clamps-are-Temporarily-Locked-into-Position-by-a-Turn-of-a-Recessed-Screw-Once-the-Speaker-is-Connected-&-Inserted-into-the-Required-Aperture-the-Locked-Clamps-are-Released-which-Then-Grip-&-Clamp-onto-the-Material-Surrounding-the-Aperture-Reverse-Procedure-