SCSI-5 (Small Computer System Interface) is a newer type of SCSI connector interface that is similar to that of the SCSI-3 connector in terms of the number of pins (68). The difference is that the pins in SCSI-5 are smaller than those of SCSI-3, so they are more densely packed together, making them harder to bend as was the common problem with other SCSI connectors. This is also why the SCSI connector is called a very high density cable interconnect (VHDCI).
SCSI-5 is also called Ultra SCSI because of the speeds that the connector and cable are capable of.
Techopedia explains SCSI-5
SCSI-5 is a smaller and more densely packed connector compared to other SCSI connectors, especially its counterpart 68-pinned SCSI-3 connectors. The leads or conductor pins are only 0.8 mm wide, allowing them to be densely packed around a hard plastic core, which lessens the chances of them bending compared to connectors with the actual pins sticking out. This also means that the connector can be made thinner and narrower, which is very useful for applications where space is limited. The special offset cable allows up to four channels to be accommodated in one card slot.
SCSI-5 was designed for high performance with little impedance and resistance, allowing for faster transfer speeds. It is the connector of choice for most advanced SCSI multiport applications such as Ultra SCSI Fast-20, low-voltage differential signaling (LVDS) technology and in RAID cards.