The classic sitter bent Billiard in Peterson's lineup, the "306", is sort of an odd-duck in terms of Peterson shape numbering conventions. Customarily the "3" at the beginning of a shape number refers to it being a System pipe. And the 306 is a System shape also, but the corollary in the classic range is also the 306. So, while the "302" is the System version of the '02', the '306' is the System version of the, well, '306'. To make matters more confusing, the '6' or '06' shape is a straight Billiard. Alright, Peterson trivia aside, it is a lovely pipe in what really is a classic Peterson shape and beautiful, ever popular, finish.
-- Sykes Wilford