The distance between the watchband posts is 0.71 inches. That is 18 MM
The diameter of the watch band holes is 1.8 MM
The thickness of the body is 11.45 MM
The length of the body is 2 inches
The width of the body is 1 inch
The two holes on the side of the body are 3 MM
The back plate and watch body use 2 1/8" wide x 1/16" thick magnets.
Here is the link to the magnets. http://www.kjmagnetics.com/proddetail.asp?prod=D21SH
Here is the link to the back plate. https://www.shapeways.com/product/3HWVK6GWS/dick-tracey-watch-back-plate