M&M's are multi-colored button-shaped chocolates, each of which has the letter "m" printed in lower case in white on one side, consisting of a candy shell surrounding a filling which varies depending upon the variety of M&M's. The original candy has a semi-sweet chocolate filling which, upon introduction of other variations, was branded as the "plain, normal" variety. Peanut M&M's, which feature a peanut coated in milk chocolate, and finally a candy shell, were the first variation to be introduced, and they remain a regular variety. Numerous other variations have been introduced, some of which are regular widespread varieties while others are limited in duration or geographic availability. M&M's are the flagship product of the Mars Wrigley Confectionery division of Mars, Incorporated.