... and building field .can last working for a long time , no Electromagnetic Interference.long life , and nice tone , the largest decibel ... 100 d/B /1m. Different size available , 3’, 4’, 6, 8’ 10’. ModelVoltageCurrent(A)Frequency(Hz)decibelPacking SizeQTYWeightCB-4BDC12V35mA50/60 85dB44 ...