Perfecto

The size

A perfecto tapers at both ends, usually with a bulge in the middle, and the foot is closed. The shape matters more than the size, and lengths vary a lot, but most run 4.5 to 6 inches with a 48 to 54 ring at the widest point.

Why smoke one

The narrow foot means you start by lighting only a small amount of tobacco. As the burn reaches the wider body, more filler joins in and the smoke fills out.

At the other end, the tapered head concentrates the smoke, much as it does on a torpedo.