From the manual it looks like a 3/4-16 if you attach via threads:
1.2 Penetrator Features
SeaNet penetrators can adapt virtually any device with a 3/4-16 or SAE MS16142-8 port requiring telemetry or 26 VDC power.
Feed-through-only models for 1 atm components; flow-through models for oilfilled, actively-compensated components.
Fluid check-valve to prevent leakage when demated (flow-through types).
Anyone know of any companies stocking Schilling parts for resale – looking for seanet throughflow bulkhead penetrators at the moment on a short leadtime basis?
We’ve been to davis and have a number of the kits, but looking for some pre-assembled units ex-davis too and will consider available options.