SCSI can be extremely confusing, and the SCSI Trade Association’s explanation of connectors is not very helpful, but doing some searching today, I some great explanations at transintl.com, specifically their Understanding SCSI Specifications and SCA SCSI Adapters pages. I had bought a pair of 5GB Fujitsu drives on clearance that had these SCA connectors, and hadn’t known what they were until today. I ended up ordering the connectors from PC Pitstop, which had the best price that a quick pricewatch/google search turned up.