I've been watching these for a while and this quite good relative to recent market prices (usually 200 or above). Note that you'll need the mounting bracket from a current backplane though.
SUPERMICRO BPN-SAS2-846EL1 4U 24 PORT SAS SATA BACKPLANE WITH FRAME | eBay
SUPERMICRO BPN-SAS2-846EL1 4U 24 PORT SAS SATA BACKPLANE WITH FRAME | eBay