I hadn't seen this product before, but a few months ago I (re)made two of my own for about $5 CAD... so, about €1.69 each (at the current exchange rate). That's a pretty impressive markup (885% if my calculation is correct?).
I gave my previous one away to someone in Cozumel, to someone thinking it'd be helpful to see above/behind them in swim throughs. I've found them very handy when leading dives, especially in a drysuit when I don't want to be moving my head all over to track people.
I gave my previous one away to someone in Cozumel, to someone thinking it'd be helpful to see above/behind them in swim throughs. I've found them very handy when leading dives, especially in a drysuit when I don't want to be moving my head all over to track people.