... 3.Being tested 2 times Public Address 6W Ceiling Speakers DSP504 Specification: ModeDSP504DSP511B/DSP511WDSP531B/DSP531WFull-range Speaker/ HF Driver4.5"x14 ... -20,000HzHole for Mounting 150x156mm102x106mmDimensions75x180mm130x120mm105x120mm Public Address 6W Ceiling Speakers DSP504