Accompanied by National Physical Laboratory Copy of Class A Kew Certificate.
The Kew "A" Rolex watches are amongst the rarest models ever produced by the company. In his quest for high quality watches, Hans Wilsdorf, the founder of Rolex, submitted already in 1914 a lady's model to the Royal Observatory. After 45 days of rigorous testing, it was awarded the first 'Kew A Chronometer Certificate'.
In the early 1940s, Rolex stopped signing the inside of their watches with the number of world records achieved and used instead the simple signature "Rolex SA". As this did not signify that they had given up the pursuit for new world records, the company undertook a challenge never attempted before. Towards the late forties/early fifties, Rolex produced a small series of approximately 140 watches, mostly mid-size Oyster Speedking models reference 5056. The watches were submitted to the Royal Observatory at Kew for chronometer testing and almost every one passed and received the desirable Kew "A" Certificate.
The present watch was submitted on 26 July 1948 and was certified Kew "A" after only one attempt on 30 September 1948. It is one of the 16 watches of the group to obtain the distinction "especially good results", meaning that its rating surpassed by 20 the accuracy needed for a Kew "A".
The Kew "A" watches are described and illustrated in Rolex Wristwatches by J. Dowling & J. Hess, pp. 270 - 275.