Mace 80372 Water Alarms (finding the RF signal)

I have had several Mace Water Alarms (#80372) for 10+ years. They are great for laying under plumbing, toliets, and washing machines. They will sound a loud and harsh alarm in the presence of a water leak. I have always used them standalone, but they also have an RF antenna output that apparently will send a signal in an ISM radio band to some type of receiver. I would like to use an SDR dongle to receive and decode the signal from the Mace sensors? I am wondering if anyone in the HA community has already done this? I have not found any information regarding the Mace frequency and data protocol. I have found a Mace sensor web site but it looks like they sell water sensing equipment for utilities and commercial interests these days rather than these little gadgets to homeowners.