Two cents was the third class rate for items under or equal to two ounces from January 1, 1949 until August 1, 1958.

This cover contained a catalog and was specified as being fourth class mail, but as it was sent for two cents it had to be using the third class rate. The damage handstamp is convenient for dating it.

This flyer could have been sent as third class mail in 1955. It could also have been entered as second class transient mail for that amount of postage at that time.

Territories and possessions used the same third class rates as the U.S. This cover went from Hawaii to Chicago in 1951.

Unsealed Christmas (and other similar) cards could be sent at third class rates from May 4, 1911 until January 7, 1968. Two cents would have been correct in 1950.