Hello, the appearance and design are different, but the functions are the same 

it could work with a nikon f-mount (d3300) to sony e-mount( a7iii). 

Plastic, I think. I bought them as a gift, but my Father loves them. They are very light and compact, but work great for things like bird watching 

As far as I know it will, I was not informed that Sony had changed the size of the lens mount on the new sony’s A7 models , that would be counter productive to any person owning a Sony lens! 

The adapter will mount the lens and you will be able to use it manually. However, my copy of the adapter does not allow the lens to be fully mounted all the way until it clicks into place. It doesn't quite make it, but it's still very solidly mounted. Also, the manual aperture linkage doesn't work properly (on my copy, at least) so exposure is controlled only by shutter speed and/or ISO. You will be able to manually focus and zoom the lens but no VR, of course. It will be a frustrating experience. Instead, get a 14-140 Panasonic zoom if you can afford it!