You want the one that says WM2.
Previously I had bought the Mainstay VG-8000 by mistake. I drew part of the circuit diagram and found out that it uses part of the 110 VAC to power pin 14 of the chip. With 12 V or 9v supply no AC voltage would be received by the chip. You might be able to trick the chip by using a 555 as an oscillator/ clock circuit. I was going to look at the waveform on mine, but I mistakenly burned it up. The mainstay sensor runs off 110 V and does not have an isolation transformer. One side of the power line is grounded. So if you put a grounded oscilloscope probe on the part of the circuit that would become the DC ground, it will short out that voaltage to the 110 VAC ground. The board will burn and the fuse for the house wiring will trip.