V46-Mount is an objective lens mount with a nominal diameter of 46 mm, which allows the continuous angular alignment of the lens in relation to the camera sensor.
Grub screws on the lens engage in a circular V-groove on the adapter. In this way, the optimum alignment can be set for high resolution lenses.
The listed versions with M45x0.75 and M55x0.75 mount are especially designed for the FA26-S45 and FA26-S55 focus adapters.