[stumpbass]

Others may have a better answer, but I believe that the SKX crystal is 31.5mm and the 150m 7002 crystal is 32mm in diameter. The 200m 7002 crystal is either 31 or 31.5mm (I can't remember which).

All that said, I believe that a sapphire crystal from a 6309 would fit a 150m 7002 case perfectly. I haven't done that personally, so hopefully others can chime in with examples.

 

[stumpbass]

...the two generations use different sized crystals. First generation 7002s use a 32mm diameter crystal, while the second generation models use a 31mm diameter crystal.

That's from Gabe's How to Buy a 7002 Diver article. So I guess it's 31mm after all.