Three build classes, one reference number

Two RM 055s can sit on the same table, carry the same reference number, cost three times different amounts, and both be described honestly by the person selling them. The reference number describes the watch the build is imitating, not the build itself. What separates the classes is inside the case, and most of it can be seen if you know which five things to look at.

Why start with the ribs?

Richard Mille movements carry silver ribs across the dial side, and those ribs change tone as the watch tilts. On cheaper builds the effect is present but shallow. On the middle class it is obvious at arm length. On custom work it is the strongest of the three. This is the one check that needs video rather than a photograph, because a still frame cannot show a change that depends on angle.

What does the plate between one and two o'clock show?

Look at the metal plate and the shape of the cut between the two screws in that zone. Entry builds leave it simple. The middle class finishes it correctly, with cleaner edges. Custom work is finished to order, which usually means the edges are polished the way the rest of the movement is. This is also the detail that exposes a mislabelled watch most often, because it is tedious to fake and easy to photograph.

What does the balance area show?

A free-sprung balance carries its timing weights on the balance itself and has no regulator arm across the bridge. Every class in this catalogue has that, so free-sprung alone does not tell you the class. What changes is the setting around it: on entry builds the shock setting sits almost level with the balance, and on custom work it sits below the balance with a small gap, which is where it belongs.

What do the spring ring and the screws show?

The caseback spring ring is a quick tell. Entry builds use a thicker ring with a single layer. The middle class is thinner and partly layered. Custom work is layered and thin. The screw heads show the same progression: flat pentagonal heads on entry builds, better defined heads on the middle class, and correct bore sizing on custom work.

What does the extra money not buy?

It does not buy accuracy. All three classes run the same family of movement, and in our experience the entry class is usually the best regulated out of the box, because fewer hands have touched it. The extra money buys finishing and part provenance. Anyone telling you the top class keeps better time is selling you something else.

How do we use this?

Every order here names the maker and the class on the order confirmation, using the same words as the comparison page. Before payment you receive four photographs and two short videos of your own watch: the dial tilting against a light source, the caliper reading on the case profile, the caseback with the spring ring in frame, and the balance area. If the class does not match what was promised, the order stops there and nothing is charged.

If you want the specifics for a single reference, the RM 055 page lists which makers build it and which class each one sits in, and the comparison page puts the six checkpoints in one table.