What is a common postal service product sold by Window Clerks?

Stamps are a fundamental and widely recognized product sold by Window Clerks at postal service locations. They play a critical role in the mailing process, as they provide proof of postage and are necessary for sending letters and packages through the postal system. Stamps come in various designs, denominations, and can be purchased in different quantities, making them accessible for a range of customer needs.

While parcel tracking devices, mailboxes for personal use, and postal uniforms may all relate to postal services in various capacities, they are not standard products that a Window Clerk would typically sell. Stamps are essential for dispatching mail, making them the most relevant and prevalent product found at service counters. The sale of stamps is also a vital component of the revenue for the postal service, reinforcing their importance in everyday transactions.