https://blog.londiniumespresso.com/the-heavy-duty-commercial-spring-lever-group-excellence-in-the-cup/
The heavy duty commercial spring lever group: excellence in the cup - Londinium Espresso
Sep 2, 2024 - it's a bit difficult to get a sense of scale, but this is a beast - to give you an idea the diameter of the wire in the spring is around 8mm.
the heavylever groupdutycommercialspring