One of the design advantages of the <a href="http://en.wikipedia.org/wiki/Serial_ATA">SATA</a> hard drive interface over the preceding <a href="http://en.wikipedia.org/wiki/Parallel_ATA">PATA/E-IDE</a> interface is the ability to hot-swap. However, to take advantage of this feature a computer must be fitted with a suitable mechanical mount to allow the SATA drives to be inserted or ejected easily. The Axstor AX-DC-3 (£89 ex. VAT) and AX-DC-4 (£99 ex. VAT) SATA drive cages provide hot-swap mounting for three drives in the space of two 5.25in. bays, or four drives in the space of three 5.25in. bays, respectively.