ROLEX gents wristwatch Oyster Perpetual Cosmograph Daytona reference 16520, U-series,...

ROLEX gents wristwatch Oyster Perpetual Cosmograph Daytona reference 16520, U-series, LC 137, superlative chronometer officially certified, stainless steel case including oyster bracelet, screwed down case back, winding crown and pusher screwed down, original tritium-dial, display of hours, minutes, constant second at 9 and chronograph, bezel with engraved tachometer graduation till 400 Units per Hour, sapphire crystal, rhodium plated movement, calibre 4030, 31 jewels, monometallic balance, Breguet- hairspring, central rotor, adjusted in 5 positions, diameter approx. 40 mm, length approx. 21 cm, original box, proof of service from June 2016 and original certificate, sold in February 1998, signs of use due to age, condition 2, discontinued model, property of a collector