31 mm Yellow Rolesor case combining Oystersteel and 18 ct yellow gold. Screw-down winding crown with Twinlock double waterproofness system. Domed bezel in 18 ct yellow gold. Scratch-resistant sapphire crystal. Slate dial with Chromalight display and long-lasting blue luminescence; "100 years" inscription at 6 o'clock in place of the usual "Swiss Made" marking, commemorating the Oyster case centennial. Each five-minute interval on the minute track is denoted by a green square, and the "Rolex" name is pad-printed in green — Rolex's emblematic colour. Perpetual, mechanical, self-winding Calibre 2232 Manufacture Rolex, with Syloxi hairspring in silicon (patented geometry), Paraflex shock absorbers, and bidirectional self-winding via Perpetual rotor. Functions: centre hour, minute and seconds hands; stop-seconds for precise time setting. Power reserve approximately 55 hours. Oyster bracelet with three-piece solid links in Oystersteel. Folding Oysterclasp with Easylink 5 mm comfort extension link. Waterproof to 100 metres / 330 feet. Superlative Chronometer certified.