Both Hypercam Fan Cooled and TEC cameras have a front female T2 thread. The specification of T2 is M42x0.75mm and the thread depth is 4mm.

The distance from the front of the flange, excluding threads to the sensor (backfocus) is 12.5mm for Fan Cooled cameras, and 17.5mm for TEC Cooled cameras. To learn more about getting the right spacing for your reducer or flattener read this article about reducer flattener spacing.

Hypercam Fan Cooled Camera has 12.5mm Flange Sensor Spacing Backfocus

Hypercam TEC Cooled Camera front thread & sensor spacing