After more research, I believe that the number of the SD card is a "date code" rather than a serial number. If so, then SanDisk's technical article has numerous errors, and this number need not be unique.
Where to Find SanDisk Model, Part Number, Date Code, for Product Registration or Warranty Replacement:
https://support-en.sandisk.com/app/answers/detailweb/a_id/53002The article states that "Serial Numbers are unique" and "Date Codes are not unique".
Code:
CFexpress Card - Serial Number on the product - YYWWLLMXXXXX
CompactFlash Card - Serial Number on the product - YWWDMTLLLXXX
microSD and microSD Express Card - Date Code on the product - YWWDMTLLLXXX + CC
SD and SD Express Card - Serial Number on the product - CCYYDDDXXXXXL
USB Flash Drives - Date Code on the product
Notice that the CompactFlash and microSD cards have the same number format, but different description. Something is wrong here.
I also noticed that USB flash drives appear to have a numbering format of CCYYMMXXXXXL.
Code:
SanDisk Ultra USB flash drive
BL121024800B China https://ounapuu.ee/posts/2023/02/15/shrinkflation/media/image-2.jpg
BL131024746B China https://www.rflashdata.com/wp-content/uploads/2015/08/Sandisk-Ultra-USB-3.0.jpg
BN140824800B China https://img.danawa.com/prod_img/500000/831/196/img/2196831_4.jpg?_v=20181120134925
BM151125257B China https://ae01.alicdn.com/kf/S1ef3815c1f57410aa7e762ea4c511edcP.jpg
BL171125745W Malaysia https://i.ebayimg.com/images/g/F88AAOSwk~Rm~A1v/s-l1600.webp
BM171226162B China https://i.ebayimg.com/images/g/2UAAAOSwD4RctZj4/s-l1600.webp
BP20120017644 Malaysia https://archive.goughlui.com/wp-content/uploads/2021/10/2021101309479736.jpg
BP2107002263W Malaysia https://imgur.com/LmbhQ25
BP2108004404W Malaysia https://imgur.com/LmbhQ25
BR220258047W Malaysia https://i5-richmedia.walmartimages.com/asr-rm/f247c89b-ca69-49e2-bae0-e86330ec52af_360_merchant_manual_12.jpg
BN22050031084 Malaysia https://sg-test-11.slatic.net/other/roc/a64b2a0622494326cd6322895f7893d4.jpg
BL2210001378W Malaysia https://ounapuu.ee/posts/2023/02/15/shrinkflation/media/image-2.jpg
BQ2304005965W Malaysia https://ugc-user-content.pccomponentes.com/IMG_658064cd8525c_20231218152709545370.jpg
BN2311001183Z China 3-pack https://cdn.idealo.com/folder/Product/201934/6/201934693/s1_produktbild_max_8/sandisk-ultra-usb-3-0-64gb-3-pack.jpg
I found this official SanDisk document that describes the marking spec of an AirCruzer wireless flash drive:
https://fccid.io/R4V-SDWS2/Label/lable-2031553.pdfCode:
CCYYMMXXXXXL
CC = Memory Capacity
YY = Year: 12=2012
MM = Work Month: 01-12
XXXXX = Technology Code (5 digits starting from 54-98-XXXXX)
L = Subcontractor Code
The mysterious XXXXX digits represent a "Technology Code", so they are probably not unique.
Other SanDisk marking specs:
iXpand™ Memory Case:
https://fcc.report/FCC-ID/R4VSDIPB/2964288.pdfIxpand Wireless Charger 15W:
https://fccid.io/R4V-SDHZB0N/Label/ID-label-and-location-4867659.pdfI also found this "Time Shift Buffer Hardware Specification":
https://account.cablelabs.com/server/alfresco/b5172002-e439-4eb4-9d67-2e5054b1d3bcThe SD card looks very much like SanDisk's cards. In this case the mysterious XXXXX digits are the "Last 5 digits from Bill of Materials".
Code:
6.1.3 SD Card Labeling
Each SD Card MUST have the following labeling on the bottom of the card etched in during manufacturing:
• Card Capacity Code (CC). See Table 4 for code mapping to capacity.
• YYDDD to indicate the year and day in that year when the card was manufactured
• Last 5 digits from Bill of Materials
• Single character Manufacturing site indicator
• Memory lot identifier
Table 4 - Capacity Code Mapping
Capacity Code Size
------------- ------
BH 4 GB
BI 8 GB
BL 16 GB
BM 32 GB
BN 64 GB
BP 128 GB