Maximum GB capacity for SDXC card slot

SDXC

Secure Digital eXtended Capacity logo; the specification defines cards with a capacity of more than 32 GB up to 2 TB

The Secure Digital eXtended Capacity (SDXC) format, announced in January 2009 and defined in version 3.01 of the SD specification, supports cards up to 2 TB,[60] compared to a limit of 32 GB[61] for SDHC cards in the SD 2.0 specification. SDXC adopts Microsoft's exFAT file system as a mandatory feature.[62]

from:

https://en.wikipedia.org/wiki/SD_card#SDXC

Mdnkl wrote:

What is the maximum GB capacity for the SDXC card slot on the new MacBook Pro 16 inch 2021?

? Depends on the brand name of SDcard and their manufactured size limit...(?)

I see a 256GB: https://eshop.macsales.com/item/OWC/SDV90P0256

What is the issue here?

ref:

About the SD and SDXC card slot on your Mac - Apple Support

I think sanDisk makes a 400GB card. You;ll have to look around. Google and Amazon are good starting places for your research.