Used means: the product was used and still in good working condition.
It may have some scratches after previous installation and signs of wear.
The product is working, tested by our technician and still under the limited warranty for a 3 month.

Warranty doesn’t cover:
Damage due to misuse of product
Damage due to using the product outside of the recommended specifications. 
Damage due to negligence or abuse 
Improper installation (including professional installation)
Damage due to clipping, overpowering and/or distortion (improper tuning)