the bender endpin

通常はネジで片側から1点で止めるが、これは コレットチャックのように円で止めるような構造。

以下 説明文
 The cone of the end pin has a fine thread, with which it can be fitted into the saddle. Advantage: This improves the oscillation of the end pin allowing perfect sound transfer.
Our experience: the instrument sounds brighter and louder with BENDER end-pin and response easier. Come and listen to the difference.
The innovative cone screw can be fitted well even with sweaty hands. Its inventor is no stranger to stage fright.
The cone screw connection and the sound conducting titanium pipe ensure that the rostrum, on which the bassist is sitting, really vibrates!
A cork inside prevents rattling, the high-grade steel point is exchangeable.
The BENDER end pin was developed by Klaus Bender, a passionate cellist and engineer. As an experienced player he is familiar with the short comings of the end pin and has thought a great deal about its function and sound and how to improve it.
Ask your violin-maker about these products (for the professional installation only!). The BENDER end pin is available in tap widths 23.5mm, 25mm, 26.5mm, 28mm. The tap corresponds to standardized drilling tools.
The rod is 600mm long and 10mm in diameter and available in carbon fibre, aluminum, and titanium pipe.
It is advisable to do a test with scrap wood beforehand, so as not to crack the saddle. Slightly moisten the drilling before screwing in the tap. That helps the fine thread press itself into the wood.  
The BENDER end pin can be dismantled very easily: Align the holes in the inner nut and outer nut as well as possible, then insert a 4mm diameter rod, thus the nuts can be unscrewed as one.