I own a VTR, but not a mini-
nautilus. But, on previous posts here, I understand that it is just a smidgen too big to fit through the ring on the VTR. It should work with the extension though. Or, you can assemble it in place. Install the base onto the VTR, fill the
tank, invert the VTR and assemble the
nautilus while the base is in the VTR.