Can you clarify this is really compatible with both 24mm and 30mm Rotor cranks spindles? That doesn't sound right to me and Power2Max's website even have separate NGeco's listed with different versions specifically for 3D24 (aka 3D) and 3D+/3D30. Just don't want somebody to find out the hard way this won't fit their Rotor cranks.

I just received a PM telling me that it's possibe to use it on a 24 mm spindle crank too :-) .
Just to make sure it's compatiible, I'd send an email to P2M (service is great there):
support@power2max.cc

Louis :-)

The 24mm and 30mm units have a different spider pattern. The 30mm looks bigger and has more bumps. THey also use different tools. The one for sale looks to be a 30mm.
https://www.power2max.com/...or-3d24-power-meter/
https://www.power2max.com/...otor-3d-power-meter/

Yes, mine is definitely a 30mm (fits "3D" (older generation with 30 mm spindle), 3D+ or 3D30 will do) version.
Sorry if my post wasn't clear at first.

Louis :-)