It's a wilcox three hole shroud but you can get repro ones made by FMA, it did not come with the helmet (the helmet is an oper8 helmet that I got from socom tactical).
https://www.fire-support.co.uk/product/fma-wilcox-3-hole-night-vision-mount-black
Edit: not sure when you say helmet mount if you mean the adapter or the night vision mount but the night vision mount is an FMA INVG and the adapter is a norotos dual dovetail (they are expensive though and can only be found on facebook groups).