The Rolex Microstella Tool

The Microstella is Rolex system to adjust the balance wheel to make sure the watch

keep the COSC standard. To do that there is a special tool to adjust the screws with.

The old tool looks like this and it's oil filled to be a little more exact and stable.

At the backside there is graduation which means 1 second per day for the low type of head nut and 2 seconds for the high type of head nut for each line.

A closer look to the tool.

Here we have a balance wheel with the Microstella screws.

Here is how it works.

A few pics of the tool in action.

The instuctions from Rolex.

And some pics of the new/current Microstella tool.

Photo credit for the new Microstella tool: Tony Axelzon