39 CFR 501.9: Demonstration or test Postage Evidencing Systems.

(a) A demonstration or test postage evidencing system is any system that produces an image that replicates a postage indicium for which the Postal Service has not received payment for postage. The following procedures must be followed to implement controls over demonstration or test Postage Evidencing Systems:

(1) A demonstration or test Postage Evidencing System may print only specimen or test indicia. A specimen or test indicia must clearly indicate that the indicia does not represent valid postage.

(2) A demonstration or test Postage Evidencing System must be recorded as such on internal provider inventory records and must be tracked by model number, serial number, and physical location.

(3) A demonstration or test Postage Evidencing System must remain under the provider's direct control. A demonstration or test Postage Evidencing System may not be left in the possession of a customer under any circumstance.

(b) All indicia printed by a demonstration or test Postage Evidencing System must be collected and destroyed daily.