It took Jeb Cheng quite a bit of trial and error ( ), but after dozens of prototypes, he ultimately arrived at the perfect design for a single-piece carabiner made from titanium. A series of slanted cuts, spaced apart to provide a balance between flexibility and rigidity without breaking apart, are placed in the arm of the carabiner. A little pressure allows it to slide backwards (the cuts only give it flexibility in a single direction), giving you enough space to slip your keys in. Release the pin/arm and it reverts to its original position. The FLEX TK6 Titanium Keychain comes in two variants, a slightly larger one with two movable arms, and a smaller, single arm variant. Machined from a single block of titanium, before being given a scratch-resistant coating, the FLEX TK6 will probably last forever, outliving keys and traditional locking systems; but so what if it’s 2050 and you’re unlocking your doors with Siri or biometrics… You can use the TK6 then to tie together the rest of your EDC! Designer: Jeb Cheng ( )