Rolex - Very rare stainless steel manual wind bracelet watch with Kew 'A' Certification. The Oyster Speedking ref: 5056, with a signed off-white dial having Arabic numerals, black outer minute track and subsidiary seconds dial, blued steel baton hands and inscribed 'Kew 'A' Certificate' - The screw down crown signed 'Rolex Oyster', the screw-down case back stamped '5056', case number 628XXX. The signed 18 jewel bi-coloured movement number 4255, inscribed 'Kew xAx Tested', 'Time with screws on balance', the freesprung Breguet type balance with timing screws, 30mm diameter, together with copy of hand written Register of Watches from The National Physical Laboratory (Teddington). During the 1940's Rolex submitted 145 watch movements to the Royal Observatory at Kew for chronometer testing. These 18 jewel movements had hand-made balance staffs, wheels and cocks, the main plates being coloured rose gold with the balance cock in stainless steel. Regulation was achieved by two screws with three spare screw holes each side for compensation. All these watches were adjusted in Geneva and overseen by the Rolex master timer Jean Matile. This movement no: 4255 passed certification on 20 January 1949. There is no known history to this watch and it is being sold for a local Cancer Charity without any vendor's commission. Movement currently functions, dial has an even patina as one would expect for a 1940's dial, hands are good and original, wear to case is likewise and unpolished, crown does pull out and pushes back however it does no-longer screw-down tight, movement is clean, riveted and spring Rolex bracelet with wear as expected and date coded 4/72 - **General condition consistent with age