It is an extremely rare version of the LS3/5A professional broadcast loudspeaker. This matched pair is full working order and sounds breath-takingly sweet, clear and realistic - the most sweet, clear and realistic speakers I have ever heard. 
The speakers are in excellent cosmetic condition, and they come with all their original packaging, which includes velvet-like cloth wrappers for each speaker. 
These are a remarkable and extremely rare pair of speakers which I am sure you will find highly satisfying.