GASHER Electronic Buzzer Alarm Sounder Continuous Sound Beep Red Green Yellow 22mm 24V 9PCS

Before buying I had read 90 dB Buzzer volume, but upon receiving and hearing myself; that is simply not the case. So I measured and got 67 dB using my cellphone app. I wanted something that I could hear through my entire house and this is only good for one room, and only very soft and difficult to hear at all in any adjacent room, add background noise of any kind and this buzzer will not be heard. This may be fine for many applications, but not mine.Also, I misread and thought these devices accommodated multiple input voltage, but I was wrong, my bad. You choose either 12V, 24C or 110V. I bought the 9-item pack because I had ideas for using all three of the voltages. I looked inside the unit to see if it would be easy to add or subtract resistance in order to get any voltage input I wanted; and it looks very easy to do. The circuit has a full-wave rectifier, MB6F, that on my 24 volts AC buzzer provides 5Volts DC to the LEDs and Buzzer. The circuit gives a pulsing on/off buzzer and colored LED. I measured 44 micro-amp current through the device. Two large, bulk-component resistors of 235 Ohms were attached to each input leads of the 24V item. So, just do the math and add input resistors to your circuit and one can use this 9 piece bulk pack for all your voltage requirements. But again, very quiet buzzer.