This simple adapter has an M8x1 iso metric thread on one side, and a BSP pipe thread G1/8-28 on the other. For reference, the BSP thread is close to being an M10x0.9 thread.
Why did I make this? Because my bowden tube kept slipping out of the original coupler, which used single-use brass compression sleeves. I didn't want to buy new sleeves and I also didn't like the system overall because it is quite easy to overtighten.
The author hasn't provided the model origin yet.