Several threads here and on Ask Andy about this very thing. Short answer: there are choices, but if you want to know that you did the right thing then get your dinner jacket Single-breasted black wool. Â 12 ounce barathea the standard, other "flat" finish or VERY subtle herringbone OK. peak lapels (grosgrain facing a little better than satin) jetted pockets (no flaps) no vents-- especially no center vent buttons covered with same grosgrain as on lapel. Â One on front of jacket, 4 on each sleeve. Trousers are Cut with a very high rise to take braces (suspenders), and generally have: double forward-facing pleats on-seam pockets single silk stripe down the outside seam;same material as on lapels. No cuffs. Ever. Cummerbund/vest issue: Cummerbunds fine. Â Same material as tie, which should be pretty much the same as the lapel material. or: vest low cut w/3 buttons. Â Lapels generally same material as jacket. Â Body of vest same material as jacket. Â Black satin back OK. Once you have one like this, then you can worry about shawl lapels, double-breasted cuts, mohair fabric, and other enhancements. Â Play it down the middle on your first one, however.