xilath If I understan you question... The diameter of the shank (stem) is 7 mm. But this shank is not round but triangled shape. I hope I could help you.

xilath No. This is absolutely silent.

xilath No. This is just a plastic caseto store.

xilath Based on description, yes. Based on reality, more like ~1700 mAh. There is some size difference too ( bigger than a standard 18650).

xilath These batteries are 18650 types, so they are compatible with EV300D goggle. But to be honest, I do not tried it with it and do not know if there are any other parameters needed.

xilath It is plastic. It is heavy enough to hold all the upper parts, but it is because of the batteries (they are in the bottom) and there are some metal parts (which are heavier).

xilath Actually this is really annoying. There is a solution, if you write reviews after you tested or tried or used the products... But otherwise that is a very serious request to allow change or modify own reviews in a later date. It could be useful not only for quality issues, but giving a better detailed review (after longer usage). It could be positive for some seller.

xilath My version has EU plug (originally, without any adapter).