A Barlow lens lets you increase the focal length of your telescope and hence the magnification. The Barlow lens is placed between the telescope and the eyepiece.
The twist-lock system allows perfect clamping on the axis. Accessories can no longer become jammed, and annoying problems with the combination of "locking groove and ring clamp" are a thing of the past. By turning the upper ring, the ring closes perfectly around the eyepiece and centres it optimally on the axis. A slight tightening is sufficient to achieve a very stable clamping, as the entire surface is clamped.
In addition to centring, the system has the advantage that it can be easily operated with gloves and can also carry heavy loads.
