Quality represents the effectiveness of tools, weapons, or other resources, usually summarized by Tier. Fine items count as +1 bonus in quality, stacking with Tier.

Thorn is picking the lock to a safehouse run of a gang renowned for Occult dealings. Her crew is Tier I and she has fine lock picks - so she's effectively Tier II. The Occult gang is Tier III. Thorn is outclassed in quality, so her effect will be limited on the lock.