Hershey's Special Dark
Special Dark is similar to a standard Hershey bar, but is made with a dark (or semi-sweet) variety of chocolate, and contains a higher percentage (45%) of cocoa solids, chocolate liquor and cocoa butter than milk chocolate. The Special Dark bar replaced the similar, if not identical, Hershey's Semi-Sweet bar in the company's product lineup in the early 1970s.
Hershey's Special Dark is a component of the traditional Hershey's Miniatures assortment, first sold in 1939.
In 2006, Hershey's began selling Hershey's Special Dark Miniatures, which included the plain Special Dark bar, along with dark bars with peanuts (similar to a Mr. Goodbar) and with crisped rice (similar to a Krackel).
Hershey's Extra Dark
Hershey's Extra Dark is a product very similar to the Special Dark. The three varieties are solid chocolate; chocolate with macadamia nuts and dried cranberries; and chocolate with cranberries, blueberries, pomegranate, and almonds. Hershey's marketing emphasizes the antioxidant qualities of these bars' ingredients. Additionally, Hershey's Extra Dark contains 60% cocoa solids while Hershey's Special Dark contains 45% cocoa solids.