J&D 250 A Split Core CT (5 VDC Output).
These are new in box current transformers/transducers and traditionally used for building energy metering. Note that they are 5VDC output at full scale for direct integration to monitoring systems, they are not 0.333 V output sensors.
Two would be needed for traditional split phase homes or three for 3-phase commercial buildings.
Full product spec's can be found at AIM dynamics where they sell for $76 each:
https://aimdynamics.com/product/JC24S-250A-V/