This is a tubular wrench.
Apart from the British "box wrench" term, "tubular" is in my experience the most common generic name for these tools. You can get a full set of them (I have one, though in metric sizes).
It looks like googling "tubular box wrench" is the best way to get the right stuff while eliminating the American ...
Disposable Tube Wrench
Cheaply stamped out of metal tubing, they are sold with products for the single use of installing that product then discarding. You can find them often with furniture and fixtures.
Not directly related to your question, but you mention in the comments that there is limited side access and you will need a lot of force to be applied.
Be aware of things called "crows foot" wrenches. These are commonly used in HVAC and heavy equipment (hydraulic) maintenance.
The wrench is a combination, made up of a "wrench part" and ...