List of Western Digital model number codes

This is a list of the trailing letter codes in Western Digital main model number codes (for exampe, the "EZRZ" in WD30EZRZ), and their meanings. Models prior to 2005 only have the third and fourth letters (for example, the "JS" in WD2500JS), but otherwise follow the same format.

First letter: Capacity and form factor

The first letter defines the unit of measurement for the capacity preceding it, as well as the form factor.

Code	Unit	Form factor
A	GB	3.5"
B	GB	2.5" 9.5 mm
C	TB	2.5" 12.5 mm (VelociRaptor only)
D	TB	2.5" 12.5 mm (VelociRaptor with IcePak only)
E	TB	3.5"
F	TB	3.5" (Nearline/Red Pro/Black)
G	GB	2.5" 12.5 mm (VelociRaptor with backplane-incompatible IcePak only)
H	GB	2.5" 12.5 mm (VelociRaptor with IcePak only)
J	TB	2.5" 9.5 mm
K	GB (prior to 2015) TB (since 2015)	2.5" 12.5 mm (prior to 2015) 3.5" (Nearline/Red Pro/Black, >= 10 TB, since 2015)
L	GB	2.5" 7 mm
M	GB	2.5" 5 mm
N	TB	2.5" 15 mm
P	TB	3.5" (Purple)
S	TB	2.5" 7 mm
T	TB	2.5" 12.5 mm
X	TB	2.5" 9.5 mm (not used)

Second letter: Business unit

The second letter denotes the business unit of Western Digital that the drive is designed for. It also indicates whether the drive supports Advanced Format.

Code	Business unit	Advanced Format?
A	Desktop PC (Caviar/Blue/Green/Black)	No
B	Nearline (Re/Se)	No
D	Raptor (prior to 2008)	No (prior to 2008)
	Self-encrypting drive (since 2008)	Yes (since 2008)
E	Mobile PC (Scorpio/Blue/Green/Black)	No
F	NAS (Red)	Yes
J	Mobile PC (Scorpio Black) with free-fall sensor	No
	Surveillance (Purple), China only	Yes
G	Mobile surveillance (Purple)	Unknown
H	VelociRaptor	Yes
K	Xe	No
H	VelociRaptor	No
M	Western Digital Internal Use	Yes
P	Mobile PC (Blue/Green/Black)	Yes
R	Nearline (Re/Se/Gold)	Yes
U	Video/Surveillance (AV/Purple)	Yes
V	Video (AV)	No
Y	Nearline (<= 4 platters only)	Either
Z	Desktop PC (Caviar/Blue/Green/Black)	Yes

Third letter: Spindle speed and cache

The third letter indicates how fast a drive spins, as well as how much cache it has.

Code	Speed (RPM)	Cache (MB)	Notes
A	5,400	2	Prior to 2017.
		256	Since 2017.
B	7,200	2	Prior to 2017.
		256	Since 2017.
C	5,400	16
D	5,400	32
E	7,200	64	Only used on 3.5" models <= 2 TB.
F	10,000	16	Prior to 2018.
	5,400	512	Since 2018. Most models with this letter under-reported their RPM.
G	10,000	8	Prior to 2018.
	7,200	512	Since 2018.
H	10,000	8	Prior to 2018.
J	7,200	8
K	7,200	16
L	7,200	32
P	5,400	EM
R	5,400	64	Purple drives always report this letter, regardless of their actual spindle speed/cache. Instead, the last digit of the capacity carries revision information.
S	7,200	64	Used on 3.5" drives > 2 TB, or 2.5" drives.
T	10,000	EM
V	5,400	8
W	7,200	128
Y	7,200	EM
Z	5,400	128

Fourth letter: Interface

The fourth letter defines the interface the drive uses.

Code	Standard	Version/Speed (MB/s)
A	PATA	UDMA 66
B	PATA	UDMA 100
C	PATA (ZIF)	UDMA 100?
D	SATA	SATA-I/150
E	PATA	UDMA 133
F	SAS	3/300
G	SAS	6/600
K	SATA (SFF-8784)	SATA-III/600
M	USB-C	USB 3.0/625
S	SATA	SATA-II/300 (Desktop) SATA-I/150 (Mobile)
T	SATA	SATA-II/300
V	USB B	USB 2.0/-
W	USB micro-B	USB 3.0/625
X	SATA	SATA-III/600
Z	SATA	SATA-III/600

See also

• List of Western Digital customer codes