An Industrial Wonder:
Tudor movements have long been obscured behind their solid steel casebacks. However, each one is a laudable feat of engineering. Designed for durability, these movements are austerely finished yet exhibit exceptionally durable architecture. Only what is required for tough, precision timekeeping is present, and hardly a frivolous detail more. Our new caseback gives you a true edge-to-edge viewing experience, so you can freely inspect the MT5402 or MT5450-U's complete balance bridge, free-sprung silicon balance assembly, and its automatic winding works. 
 
An Efficient Design:
Our team approached this design to create a minimalist solution that does not compromise the ergonomics of the original watch. Maintain a slim profile of the cult-classic Black Bay 58, allow a full view of the movement, and preserve the watch's durability. The solid sapphire crystal allows full view of the movement, and is sufficiently thick to provide a full 200m of water resistance of the original BB58 and its 'Coke' GMT variant without increasing the height of the case. Multiple colorless anti-reflective coatings on the dome's underside suppress errant light, ensuring you a clear view of your Tudor Black Bay's movement. 
 
No Expense Spared:
Staying true to the design of the original caseback is critical to us. To this end, we have carefully finished the 316L stainless ring with the same finishing techniques: Sandblasted locking flutes, and circular brushing applied on the periphery of the caseback. The finishing stays true to the no-frills spirit of this professional diver's watch.
 
 
With this caseback, showcase the genuine, beating heart of your Black Bay 58 with unmatched clarity!