The Choate Tool Benelli M-4 +2 Extension might work with the AKSA S4 since it is an M4 clone. However, since the manufacturer does not state any other gun besides the M4 as being compatible then fitment cannot be guaranteed.
It does absolutely work on Turknelli clones.
I have the same one as yours and the only thing off about it is the color.
it's a gray color but I was gonna paint it anyway.
Keep in mind that you'll probably only be able to fit 6 in the tube and almost but not quite 7.
As far as I can tell it's an issue with the real Benelli as well.
It's a 1/1 clone, you're good to go bro.