Line master vise purpose?

[Swingpress]

As the title says, I have a picker trying to sell me a Line Master vise. What were they primarily used for? Any idea as to what they are worth? It sure is an odd looking duck!

 

[cvairwerks]

Circuit boards and similar type work. The PanaVise 300 version is $66 new.

 

[Swingpress]

Circuit boards and similar type work.

Well, ****...

Thank you for the info though!