A Robusto is a cigar of roughly five inches in length by fifty ring gauge. It is, by a wide margin, the most popular premium cigar vitola in the contemporary market, and the one most blenders use as their reference shape when developing a new line.
The Robusto’s success has a practical explanation. At five by fifty, it smokes for roughly forty-five minutes to an hour, which is long enough to deliver a complete first-third, middle-third, and final-third arc but short enough to fit into an evening without dominating it. The fifty ring gauge gives the blender enough room to construct a complex filler bunch, while the five-inch length keeps the smoke cool and the burn controlled.
Notable Robustos worth seeking out: the Padrón 1964 Anniversary Robusto, the Arturo Fuente Hemingway Short Story (a Perfecto, but Robusto-sized), the Romeo y Julieta Short Churchill (a Cuban Robusto), and the Oliva Serie V Melanio Robusto. Each one shows what the vitola is capable of in different hands.
For more on cigar construction and how vitola affects the smoking experience, see The Anatomy of a Cigar.