A theorem walks into a bar...
The Klein Bottle is a mathematical joke: a surface with only one side. This one feels just right in your hand and opens bottles with ease and style. Built to last in steel, it's the perfect touch for any math fan's kitchen.

Yes, it really works!

Klein not-a-bottle-opener is here.

US Size 7 US Size 8 US Size 9 US Size 10 US Size 11

US Size 12

For when you realize that being lost in the jungle and completely mad has its perks.

The default Ring Size is US 9.