# TRL5 - Breadboard version in relevant environment The difference between TRL5 and [[TRL4 - Breadboard version in lab]] is that you’re now in a ‘relevant’ environment. What does it mean to go to a ‘relevant’ environment? It has to do with giving up control over the exact inputs. You still have meta-control over the environment but you can’t control exactly the inputs that the environment creates for the system. In a software context this could look like the first time you let a real customer or someone not on the dev team use the system. In health-focused biotech, the ‘relevant’ environment would be a mouse or similar animal that’s a proxy for humans. <!-- #evergreen --> [Web URL for this note](http://notes.benjaminreinhardt.com/TRL5+-+Breadboard+version+in+relevant+environment) [Comment on this note](http://via.hypothes.is/http://notes.benjaminreinhardt.com/TRL5+-+Breadboard+version+in+relevant+environment)