Rotational Post and Holder
* Spring-loaded design supports the post, even when the locking screw is loosened
* All post holders are precisely bored, providing full two-line contact, to minimize wobble
* Precision bearing design provides smooth rotation to arbitrary directions.
* Enable access rod around the rod axis 360° rotation without changing the other location parameters
* M6 threaded holes in the bottom to facilitate connection with other optical bench
* Center hole 12mm