HP 921406-001 speaker kit is the replacement speaker assembly identified in the HP service guide for the Pro x2 612 G2 tablet.
The assembly includes the tablet’s left and right speakers. In the service procedure, the antenna wires are released from their routing before the speakers are lifted out, so the part is handled as part of an internal repair rather than as a standalone external speaker.
This part is intended for servicing the Pro x2 612 G2 speaker system. HP’s guide instructs that the tablet be powered off before removal, then the speakers are lifted out and the procedure is reversed to install them.