If you're looking for the most minimalist way to carry your keys, The James Brand's Midland Key Hook will lighten your load and free up pocket space. It's milled from a solid piece of titanium - it's one piece, no moving parts. The deep-carry hook fastens securely on your belt loop, and the included titanium keyring secures your keys aside your hip. And the included bottle opener surface makes sure you're ready when it's time to let loose.
