DOCKCASE Magsafe M.2 SSD Gridfinity Holder
They don't seem to sell the exact model I have anymore but here is a similar one:
https://www.amazon.com/DockCase-Enclosure-PD-Protection-Compatible/dp/B0DSN3PHXX?th=1
Fits into a 1x2 Gridfinity and is 6u tall.