For sale is one platinum matched pair of genuine EF91 6AM6S M8083 made by Mullard in Mitchum tube plant in Great Britain. 

Both tubes are matched within 5% (platinum pair). They are perfect substitutes for Little Dot I+ headphone amplifiers

Mullard codes and date of production are clearly visible on photos, 

See also my other auctions and visit my eBay store www-tubes.rs  for more vintage tubes and tube parts.