A nice touch is the gentle tension in the terminals on this unbranded relay, which grips wires without crimping them hard.
Versatile 5 AMP 110V/120V Electromagnetic Relay with Socket Base & LED Indicator
You will find that the Emergency Stop Module gives you a reliable way to halt operations quickly.
A nice touch is the many hobbyists recognize from various repair projects.
You will find that this Power Relay/Battery Isolator simplifies adding accessories without draining the main battery.