There has been quite a change since the original Mk 1. If you want a drive that attaches to the seatpost, the Mk 1 is a good option. The latest design is a bottom bracket mount. Go to this thread for more info https://endless-sphere.com/forums/viewt ... 93ac8ebc74
I haven't built any drives for about 9 months as other commitments have got in the way. Good news is that I have continued to use the current design drive on a daily basis over this time and it has served me well. With the many thousands of kms covered with the drive, even further refinement on the design has been made. Stay tuned on the main sales thread. Updates coming very soon.