Review on Senzeal Connector Terminal Automotive Electronic by Jeremy Bradford

Terminal hole tolerances are tight. That means you actually have to slide the terminals into the relay to latch them. That's fine when they're sitting, but if you try to use them with a heavier wire (12 ga) they're going to have a really hard time sitting. I would not recommend them if you are using them for real load carrying equipment (electric motors, lights, fans) as they work best with 16ga or less cable.