Maybe this chart is useful.... see measure "2".
To add, I have the following measures for the Explorer II 216570:
- Bezel edge to bezel edge: 41.5mm
- Case diameter incl. crown: 45mm
- Case Length: 48.7mm (lugs at 6 to lugs at 12)
- Case thickness: 12.40mm incl. caseback and crystal
- Lug width: 21mm (tapers down to the last link before clasp which is 15mm)
- Clasp length: 35mm (including the the small protution at the springloaded tip: 36mm)
- Crown diameter: 7mm - same size as Milgauss 116400 crown (standard TwinLock is 6mm)
- Crystal diameter: 33.5mm
- Dial diameter: 30mm (from INNER edge of rehaut to the other)
- Width of minute hand: 2mm
- Width of indices: 2mm
- Weight incl. all links: 157g (same weight as Milgauss 116400)
Plus these measures of the Deepsea Sea-Dweller 116660:
in milimetres:
1. 32
2. 43
3. 48
4. 21
5. 28
6. 52
Dial diameter: 28mm
Case thickness: 17.68mm