The HP 840745-001 optical drive connector board is a laptop part for connecting optical drive hardware. HP lists it as SPS-ODD BD, and the board is installed before the optical drive hardware is added.
The part is listed for HP ProBook 650 G2/G3 and 655 G2/G3 notebooks. HP Support also names it as a possible option for ProBook 640 G2 and G3, depending on the machine. This is the connector board itself; the listing does not describe it as the optical drive.