Sweet William Cigars are a type of tobacco product made by the UNSC, and enjoyed by a large number of humans. They are considered a luxury item.
Chief Petty Officer Mendez smoked these. He kept a box of them on his desk in the Highland Mountains. Dr. Halsey, however, was not fond of them.
Colonel Robert Watts smoked these also, he had them delivered regularly to his base at Eridanus Secundus. The Spartans recognized this, and placed a NAV Marker Transmitter on the box, which allowed them to find and capture Watts.
Others who smoked these Cigars include Captain Jacob Keyes and Admiral Micheal Stanforth.
NOTE: They are likely named for the Sweet William flower that is native to Europe. It is possible that Sweet William flowers are used in the making of these cigars.