Zorki 3M with unusual lens

[mrmonde]

I've just purchased a Zorki 3M FOR £30, attached was a lens I don't recognize, it's a TRIXAR ANASTIGMAT 1:3,5 50MM. Can anyone tell me about this lens and is it a valuable find, it's in ex. condition.

 

[xayraa33]

http://www.rangefinderforum.com/forums/showthread.php?t=73213