The 2TB WD Red NAS hard drive (WD20EFRX) by Western Digital is a high-performance internal desktop drive designed for use in PCs and Macs. With a rotation speed of 5400 RPM and a storage capacity of 2TB, this SATA III hard drive is ideal for NAS systems. Its red color and compact 5.25-inch form factor make it a stylish and efficient choice for expanding storage capacity in your system. With a cache size of 64 MB, this HDD-only drive is perfect for storing large data sets and files for both personal and professional use.