27 CFR §19.190

1. (a)When required by the appropriate TTB officer, the proprietor must provide a secure cabinet equipped for locking for use by TTB.
2. (b)If one or more TTB officers are assigned to a distilled spirits plant to supervise operations on a continuing basis, the proprietor must provide a suitable office at the plant for the exclusive use of the TTB officers in performing their duties. The appropriate TTB officer will determine if the office facilities are suitable.