Genuine GE part number WB6X10139.
This is a OEM Part.
It is a Microwave Roller Guide Ring Assembly.
Diameter of the ring is 8-7/16" (measuring only ring diameter, not including the rollers).
It has 3 rollers attached to it.
Stamped on the ring are number's DE72-60180 SPS, SSQTR 2 Guide-Roller, SA/SEMA-2-2.
Replacement for numbers AP2016749 and PS227854.
Designed to fit specific General Electric manufactured Microwave models including Hotpoint and RCA.