Master Ultra Thin 34mm Variations?

Sep 21, 2016,04:47 AM
 

I've been researching and pondering this for a while, it seems there are two variations of the original MUT (34mm with caliber 849), an earlier one which has the solid caseback and a later one (more commonly seen) with a sapphire caseback. Both reference numbers seem identical (145.8.79)


Does anyone know which year this transition is made and whether there may also be solid caseback MUTs with caliber 839 instead of 839? I've attached two photos for reference.

Thanks!







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As far as I remember....

 
 By: watchme : September 21st, 2016-07:16
The MUT 34mm launched in 1992, started with Cal 839, but introduced Cal 849 in 1994. The exhibition back debuted in 1999 with the Master Blacks - MUT, Master Moon, Geographique, etc. In 2000, the silver dials began to have exhibition backs. My favorite wa... 

Thanks! it's hard to get information about this, do you know anything about thickness

 
 By: Ed. W : September 21st, 2016-07:20
I keep seeing 4.2 mm but also reports of 5.5 mm (for both the solid and display back...) Also I just noticed the ref may be different after all: Solid back is 145.8.79 and display is 145.8.79.s

Up until about 2002, the books always stated...

 
 By: watchme : September 21st, 2016-09:43
4.2mm. There are a couple of great articles on the piece on the Web, this being one of my favorites: www.timezone.com Cheers! -Dean

I can measure tomorrow to confirm

 
 By: Tim_M : October 1st, 2016-20:06
Mine is the steel Master Black from the late 1990s, so I can can offer a caliper-verified measurement of the 145.8.79s with display-caseback tomorrow. My understanding always has been that the display caseback added 1mm to the thickness of the solid-back ... 

I don't see many manual wound watches produced by JLC.

 
 By: MoonWatchMan : October 1st, 2016-18:27
The sapphire caseback is a beauty

Does anyone know what year they stopped making these?

 
 By: Cool Breeze : November 1st, 2016-04:39
I'm particularly interested in a stainless, silver dial, sapphire case back. Thanks!