Not M.2 compatible
The description reads: "Argon Forty ONE V3: A sleek, stylish and compatible SDD M.2 case for Raspberry Pi".
Except that the Argon Forty ONE V3 is not M.2-compatible (as was the case with its predecessor, the Argon Forty ONE M.2).
As stated in the documentation supplied with the case, there is a second model, the "Argon Forty ONE V3 M2 NVMe PCIE Case", as well as an extension, the "Argon ONE V3 M.2 NVME PCIE Expansion Board Only" (both perfectly unobtainable on the site), which allow this compatibility.