US Stamps - Q - Parcel Post
If you needed to send a parcel by US mail, starting in 1912 you could use parcel post stamps. They indicated the pre-payment of postage on parcel post and ensured its handling as such. Parcel post was an economical way to send packages too heavy to go through the regular mail service. In all, twelve stamps with different denominations were issued. They are listed in catalogues as beginning with a "Q", and there was even a "JQ" stamp issued-a postage due parcel post stamp. Now you can pay parcel post with any kind of stamp.
