It looks to be …
They operate on 915 MHz. This band is used in the Amateur Radio Service and the Location and Monitoring Service (LMS) and it is part of (and could be referring to the entire range of) the ISM (Industrial, Scientific, and Medical) bands of 902–928 MHz. Also it is a microwave frequency, meaning it can cause dielectric heating of organic matter, if the power is strong enough.
From Hubitat Elevation forum.