Part PHAG-A011VBFA is the brush clamp for the Sharp ECTU2609 and ECTU4609. It is the piece that holds the brush roll in the nozzle so the roller stays seated and turns on its proper axis.Clamps crack from the same shock loads that break end caps: the machine dropped on its nozzle, or something solid drawn under the roller and stopping it dead. Once the clamp is loose the roller shifts as it turns. You hear it as a knock or rattle from the nozzle, the belt starts to run off center, and carpet agitation gets noticeably worse because the bristles are no longer held at a consistent height.Replace it with the brush roll out, and inspect the roller bristles and bearings while the nozzle is open. Check your model against the ECTU2609 and ECTU4609 before ordering.