mailers may also receive information on addresses that are undeliverable for reasons other than a customer move (i.e., nixie notifications) — United States Postal Service.
A piece of undeliverable mail that's returned by the post office Depending on the quality of the lists, mailings can result in hundreds or thousands of nixies Some list rental agreements include a refund for nixie quantities
A piece of mail matter which cannot be delivered, either because no post office exists at the place to which is it addressed, or because there is no place of the name mentioned in the designated State, Territory, or the like