This is the kind of back that, depending on what 4x5 you use, either slides in under the GG, or uses the Graflok to attach to the camera body.
It does not rotate on its own.
On my Linhof Technikardan, the Toyo back is attached via the Graflok back.
On many Toyo cameras, this back will slide in under the GG, no removal of the back necessary.
Are you sure it slides under the GG on some? That looks way too fat. I have a Calumet back for similar use and it is only about 1/2 inch thick for the purpose of replacing a 4x5 holder. Just asking for others who might be considering this. GLWS, Bob.
I have read that it will slide under many Toyo GGs, they have slightly more clearance.
It almost fit under my Linhof's, just a few more millimetres would have done it, but I didn't want to force it.
Thanks for the query.