That product has been developed in December 2012 to provide possibility to tune inductance in a smooth way.
It was designed mainly for a QRO versions of an amplifiers/antenna systems.
Presented KIT Futures:
Threaded ABS tube with a ...
This strong design allows you to install DIY antenna on a mast, now problems with isolation or rigid connection is solved and easy to achieve.
It is recommended to use two sets for longer antennas
Tubes diameters:30/30mm ...