Rolex Sky-Dweller Watches

How it works: Rolex Sky-Dweller annual calendar, second time zone and Ring Command

The Sky-Dweller is a travel watch with a calendar built in. The center hands keep the time where you are, and the off-center disc carries home time on a 24-hour scale. Small windows beside the hour markers stand for the months in order, and the one filled in is this month. The date sits at three o'clock under the Cyclops. The calendar tells the short months from the long ones, so it needs setting only once a year, at the start of March. Its fluted bezel, which Rolex calls Ring Command, picks what the crown sets.

Steel or two-tone: stainless steel Sky-Dweller or two-tone yellow gold Sky-Dweller

Steel is the Sky-Dweller to wear everywhere. The listings say Oystersteel, which is simply Rolex's steel, and the fluted bezel on a steel Sky-Dweller is 18K white gold, so it reads white, not yellow. Two-tone keeps the steel case, but its bezel, its winding crown and the center of its bracelet are 18K yellow gold. It warms the look, and on a daily watch that gold shows hairlines first. An all-gold Sky-Dweller is a request for the desk, which sources through the trade.

326 or 336: Sky-Dweller 326934 or 336934, the two generations

The first three digits of the reference give the generation. A 336 is the later one. A 326 came before it. On the wrist they are hard to tell apart, since both are 42 mm with the same bezel and dial layout, so let the dial you love and the year on its card settle it. Then look at the final digit, which gives the metal. A 4 there is steel with the white gold bezel. A 3 there is the yellow gold two-tone.

On the wrist: how the 42 mm Rolex Sky-Dweller wears, Jubilee or Oyster

A Sky-Dweller wears large. Most wrists over seven inches carry it well. On a slimmer wrist, compare it with the case of the watch you wear now. Choose the Jubilee if the watch goes with a jacket most days, since its small links soften a big case. The Oyster, with its three wide links, suits the weekend better. The bracelet is sized to you by its links, and the desk knows whether the spares ship with yours.

Papers and diamonds: Sky-Dweller box and papers, iced out and final sale

The short lines after each listing's main paragraph say whether the Rolex warranty card comes along, and most here have one. Any box is an extra you choose. The year shown normally comes from that card. On an iced-out Sky-Dweller, look for the word aftermarket, which means the diamonds went on after Rolex made the watch. Nothing goes on the site until our watch team has had it in hand. Watches cannot be returned, so bring any doubt to the watch desk first, on the live chat with the reference number, or by text to 212-872-9692, where a person replies from 10 AM ET. The shipping policy tracks every parcel and gives a watch in stock two to five business days to leave us.