I think the 43 mm caps. I understand the 43 mm cap fits the $10 strikes almost perfectly. And is smooth on all sides. Without a white or black ring inside.
I also understand there is a 44mm clear cap made by a company named Light House. it has an outer ridge that when all placed in a box they do not rub together, no fine scratches. But they are just a tad bit loose inside the case.
Thoughts from anyone.........................