The ATTO ThunderLink TLN3-3102-D00 is actually a Thunderbolt 3 ConnectX-4 with two independent SFP28 ports.

They're available on eBay from various sellers- here's a listing with multiple available:
Another, need to source a power adapter though:
There are some cheaper one-off listings if you look around (sold after this post, naturally):
Out of the box, the 3102 is capped at 10GbE and won't link at 25GbE. That's easy enough to fix. You can go to ATTO's download page, flash the TLNS-3252 firmware (fw_TLNS3252_32.1010.bin in the same zip file), and 1/10/25GbE will work.

Note that even new, these don't come with Thunderbolt cables. You have to supply your own. They also require PCIe tunnelling to work (TB3, TB4, USB4- not a normal USB-C port).
Here's what one looks like outside the all-metal case. The fan is not bad.

Now my Mac mini has 25 gig!

They're available on eBay from various sellers- here's a listing with multiple available:

ATTO Technology ThunderLink TNLS 3102 40Gb Thunderbolt 3 to 10Gb (SFP+) Adapter | eBay
Two SFP+LC optical modules included. Pluggable optical SFP+ LC module and Quad to Serial Small Form Factor Pluggable Adapter included. Connector Type Optical SFP+ LC (included). Dual port 40Gb/s Thunderbolt 3 with DisplayPort and device daisy-chain support.
www.ebay.com
Another, need to source a power adapter though:

ATTO TLN3-3102-D00 Dual-Port Thunderbolt 3/4 to SFP+ optical 10Gb Adapter w/SFP | eBay
Has SFP transceivers;. No AC adapter;. We want to hear from you! • Inability of a hardware item to function with a specific software application or system. • No rack rails or mounting hardware are included unless specifically stated above.
www.ebay.com
There are some cheaper one-off listings if you look around (sold after this post, naturally):

ATTO Thunderlink Thunderbolt 3 to 10GbE Network Adapter | eBay
POWER CABLE NOT INCLUDED. 10Gigabit Ethernet Card with Thunderbolt 3 interface. Optical Fiber support with 10GBase-X technology. Product Key Features.
www.ebay.com
Out of the box, the 3102 is capped at 10GbE and won't link at 25GbE. That's easy enough to fix. You can go to ATTO's download page, flash the TLNS-3252 firmware (fw_TLNS3252_32.1010.bin in the same zip file), and 1/10/25GbE will work.

Note that even new, these don't come with Thunderbolt cables. You have to supply your own. They also require PCIe tunnelling to work (TB3, TB4, USB4- not a normal USB-C port).
Here's what one looks like outside the all-metal case. The fan is not bad.

Now my Mac mini has 25 gig!
Last edited: