What is the difference: Z3XC vs Z3XB?

Z3XC is the upgraded version of Z3XB

Design and build

The Z3XC is pretty much identical to the Z3XB in terms of design and build, just as you can see from the pictures.
Both Z3XB & Z3XC is using 3 cameras with a very similar mount.

Lenses

The Z3XC has a major advantage over the Z3XB when it comes to lenses

The Z3XB is using the orginal iZugar MKX13 Fisheye lenses with FOV185.
The iZugar MKX13 Fisheye lenses is the first mini 185 fisheye lens rated at 10MP, it provides right enough overlapping for stitching and high resolution.

The upgraded Z3XC is using iZugar MKX19 Fisheye lenses with FOV194.
The iZugar MKX19 Fisheye lenses provides more overlapping which make the stitching result and color blending more promising.
This special FOV194 fisheye lenses that designed and manufactured by iZugar is a almost theta lens, which make it possible to restore the image in an undistorted way.