Santi Thermovalve - Apeks or Si-Tech?

[guruboy]

Does anyone know how to tell an Apeks thermovalve from an Si-Tech thermovalve? I’m assuming the diameter of the threads is different but can’t find any numbers.

All the stores offer two options but don’t mention the technical differences.

 

[tbone1004]

hole size is different. Apeks is bigger. If you have an Apeks hole, the Si-Tech will fit, but not the other way around