The problem here is that you may not realize to what quality is.
Delivered is a frame which is not able to withstand its own weight to here. If you want to hang the picture, so warps due to the length and weight of everything, so that the "glass" (plastic) and the back wall fall right out of the socket out of the frame. And as I said in the default state of an image: hanging!
The fact that rear wall and glass are not available due to the unstable framework also fit each other occurs in some places to withdrawals, where the plastic glass is a few millimeters away from the image. Through the anti-reflective effect the image can thus no longer clearly recognized here (frosted glass effect).
I can therefore only advise other buyers, to build its own framework if they need such special formats. For 50 should be there already much better hinbekommen (little skill required).