Hex-Plus L-Key Set, 9 Pieces

Cheap hex keys are where good screws go to die. The steel is soft and the corners are sloppy, and one slip inside a stainless bolt leaves carbon behind, which turns into rust a week later. These are full stainless, vacuum ice-hardened, and the Hex-Plus grind bears on the flanks of the socket instead of the corners. In practice that's about 20% more torque before anything starts to round.

The details are what embarrass other sets. Sizes are etched big enough to read at arm's length. The ball ends let you drive at an angle without camming out. And the clip releases one key at a time instead of dumping all nine on the floor, which sounds minor until you've owned the other kind. Bike mechanics and machinists settled on these years ago.