The Datejust is the best selling Rolex model on the market, and has been for decades. It was first introduced in 1945. The gents model is 36mm in diameter (and 26mm for the ladies) and typically came on a Jubilee bracelet. Rolex seems to have changed their tradition on this, and is sending more Datejust models out the door with the Oyster band. Models with smooth bezels exist, but are more scarce. Most have the fluted bezel, which is 18k white gold on the steel model.