After months of intensive development and weeks of rigorous testing, they have finally arrived! 
 
Got a 3861 Speedmaster Professional Moonwatch, and want to see that Co-axial Master Chronometer movement while making your watch more ergonomic? Swap out the solid caseback with this precision-engineered ultra-thin exhibition caseback, and be able to view the movement at your leisure!

Revolutionary Form:
This new caseback continues to push the boundaries of what is possible. We have carefully engineered an inverted double-bevel profile that reduces the steel volume, allowing the caseback to virtually disappear into your wrist. Of course, it wouldn't be a SWP caseback without an overall reduction in height. This new profile, meticulously optimized for slimness, will reduce your 3861 Speedmaster height by approximately a quarter of a millimeter.
 
How it's Made:
Our caseback consists of an outer ring, which we precision machine from 316L stainless steel. Then, we sandblast the slots for the opener tool to eliminate machining marks. This also provides contrast to the polished double-bevel, a feature of pre-moon references which we recreate on each caseback to stay true to the Speedmaster's roots. 
 
After polishing the double-bevel to a mirror finish, the steel ring is carefully fitted with a scratch-resistant sapphire crystal. We apply a colorless, multi-layer AR coating to it, ensuring clear viewing and photos of your Master Chronometer movement.

Will This Fit My Watch?
This caseback is designed to fit the new 2021 Speedmaster Professional Moonwatch with 3861 movement. These particular references are:
- 310.32.42.50.01.002
- 310.30.42.50.01.002
- 310.30.42.50.01.001
- 310.32.42.50.01.001

Installation:
Fitment is simple – You will need to remove your old caseback and dust cover. Then, screw on the new exhibition caseback and enjoy the view! No additional parts are necessary!

Detailed Specifications:
Caseback Height: 2.5 mm (excludes threaded section)
Materials: Hypoallergenic 316L Stainless Steel, Sapphire Glass, Polymer Crystal Gasket
Water Resistance: 50m (Note: all other watch gaskets, such as those in the crown and pushers, must be properly maintained).

Please note that the watch and movement are only shown for demonstration purposes, and are not included in the scope of the items this listing is for.  

If you have any questions, send us a message!