Having used the two pin system for years i swapped to the euro pin system because that is all that some manufacturers extensions will take.
Used for freestyle ,bump my hump and waves and it sheered off!!! after two months.
i know this is unusual and probably 'bad' stainless ... but what is the strongest system?
Both do still have the central bolt going up to either the pin or cup though.
Pissed off as big gouge in board, but lucky not offshore when happened.
Picture shows sheared off europin still stuck in extension and two pin system on left.