Yes they use a 24 volt DC coil power relay {I had to look inside
} and not the ratchet used by X10.
Even the older discontinued 2000 series modules used the same 120 volt AC coil power relay. They used in the earlier revision Insteon/Icon modules and are also quiet.
One reason I had used the Smarthome 2000 series modules. NO CLUNK!
Well the curious side of me had to try it. I used the six digit ID number and tried to add it to my Insteon system. It added no problem and was found as a 2856S3B Icon Relay 3 pin.
This maybe an early unit only thing. They may have just relabeled some modules until the new X10AM466s are in production. With X10 only firmware.
I would not have even had a clue. If they didn't forget to remove the six digit ID label from the unit.