I just received another CWC G10 watch. I believe with this watch, my CWC G10 collection is complete. Why? Well I have all the G10 for the different branches of the military. I have the W10 for the British Army, 0552 for the Royal Navy, 0555 for the Royal Marines and 6BB for the Royal Air Force. The serial numbers have been removed (Photoshop).
I do know that there are also 3 case thickness of the CWC watches. I believe that I have all 3 and also the 2 different thickness of the case back. The W10 is the thick case CWC and it is fitted with the thick case back. The 6BB is the thin case CWC and it is fitted with thick case back. Both the 0555 and 0552 are the middle thickness case and it comes with the thin case back. The case back on these 2 watches may look different in thickness, but the overall thickness is the same. More on this later.
The question is how do we tell the difference? I measure the thickness of the shoulders at the crown. The thinnest case measures 2 mm at the shoulders. The medium case comes in at 3 mm and the thick case comes in at 4 mm. I have no idea why the case are design such. The different case thickness can be seen in the photographs below.
As for the case back, I measure the 'flat' or side of the case back. But as you will see later, the case back on the 0555 and 0552 have different side thickness. However the overall thickness is the same as the 'slope' is also different.
From the photograph below, we can see that the watch at the top is the thick case and the one at the bottom of the pile is the thinnest. The two in the middle is of the medium case thickness.
Another view. If you look closely, you will notice that the case back thickness of the middle two watches 'looks' different. The thickness of the case back of the second watch from the top looks thicker as compared to the one below it.
The case backs. The bottom 2 watches have the thicker case back. The top two actually have the same (overall) thickness case back. The top one looks thinner. However the overall thickness is the same. The slope on the top watch looks longer as well. This is due to the thinner side wall of the case back.
Another view of the 0555 and 0552 and the 'different' case back. As you can see the overall thickness of the watch is the same.
Now if only my Precista G10 watch collection is just as complete.