44 Over 81

One major variety is the 1844/81 Braided Hair Large Cent (Penny) Overdate error. This coin features the 1844 date struck on top of an inverted or upside-down 1844 date. This can be identified by noticing parts of the underlying "81" being seen under the overlying "44" at the end of the date. In some cases a very small portion of a "4" can be seen under the "8".