Stun Calibrator
Stun Calibrator is an artifact that gives you 1 Stun Charge on your first attack each turn.
Clarification
Once it's given you Stun Charge for the turn, its sprite changes to its grayed-out variation.
Strategy
What this usually means is that your second attack each turn stuns - an amazing defensive tool that can often give you a way out of sticky situations. In particular, stunning The Cobalt's main cannon is one of the best ways of dealing with it.
The only caveat with this artifact is that you have to able to attack twice in a turn consistently to take full advantage of it. It is often quite worth your while to draft in a way that lets you do so. Some ways you can ensure it's useful include upgrading your Basic Shots instead of removing them, drafting multi-attacks like Sear (where the Stun will apply to the second attack), and card draw effects.
Stun is an especially strong resource for Jupiter Drones, giving them an easy way to stay alive in fights.