According to Blackmagic Design's website, the URSA Mini Pro 12K needs about 1,000 MB/s of write speed if you're going to take advantage of all of the recording modes such as large resolutions and high frame rates.
The Samsung T7 Shield can handle read & write speeds of 1,050 & 1,000 MB/s, is available in 1TB, 2TB, and 4TB.
From my experience using the URSA 12K, I recommend you go with at least the 4TB option. No matter what recording formats you choose with the URSA 12K, it's going to eat through data fast.
There are certainly other options out there for SSDs, such as getting Blackmagic's own URSA Mini SSD Capture Device for 2.5" SSDs. But this is certainly a very expensive option—more expensive than getting an entire 4TB with the Samsung T7 Shield!
This also doesn't include your costs of also having to buy a 2.5" SSD to go with this adapter.
One of the most trusted brands in this space is SanDisk, although, they're been getting a lot of heat in 2023 due to drive failures with their SanDisk Extreme Portable SSD.
So, with SanDisk, even if the prices or discounts looks enticing, you might want to hold off to see how they handle their product failures.
The most important thing you need to consider is read & write speeds of the SSD.
The Samsung T7 Shield SSD:
Which is the same as the SanDisk Extreme Portable SSD:
So which should you get?
Well, here's a post from X (previously Twitter) that might be worth considering:
Here's a link to the Samsung T7 Shield on Amazon.
However, it's only fair to you that I now mention the downsides. ⤵
Cutting to the chase, the biggest downside is using a cable.
It doesn't matter how robust the cable is, it's still an unsecured, loose piece of equipment that can easily get hit, damaged, or simply loosen over time.
There are just more points of failure.
However, if that doesn't scare you off, and the price sounds enticing, you may very find Samsung T7 Shield is a great fit for you.