We have started this brand new FPV goggles project since Aug 2016 and made our prototype in Jan 2017.
With this prototype we conducted some tests and participated in exhibitions & events.
We applied what we have learned through this experience to pre-production model of Kaptain G.
Here are some changes we have made to our pre-production model:

A - Face support units: For your comfort of wearing.

B - Head band clip: To replace straps without disassembling.
C - Optics: Moved forward for bigger FOV.
D - Diopter slides: For corrective lenses for near-sighted pilots.

E - Power button: Increased its size with LED lighting.
F - Ventilation holes: Increased numbers for efficient air circulation.
G - Channel buttons: Increased size and changed function. (e.g. Long press to change bands)

H - DC Port: Diameter of the port changed from 3.5mm to 5.5mm for compatibility.
I - IPD: Changed to gear-type.
J - Ventilation holes: Increased numbers for efficient air circulation.
I am very impressed with the changes and updates. How are you determining who receives the most recent pre-production units for evaluation in the fpv community?