The concert uniform for the NUCS is as follows:
Men wear black tuxedo jackets, black bow ties, black pants (either tux pants or plain dress pants), black shoes (shined), black socks and white shirts. The shirt could be a tux shirt or a plain white dress shirt. The NUCS has a few tux jackets to lend to men who may not have their own; men must provide their own bowties.
Women The chorus will lend each woman a long black skirt. The skirt must be returned after the performance. Each woman will wear a formal long-sleeved black blouse (you must purchase your own blouse), black formal (but comfortable) shoes, and black nylons.
Keezers in Cambridge is a good place to buy (or rent) tuxedos.
Cousin's is in Connecticut, but you can buy tuxes and gowns on line.
Cheap Tux Dot Com is another on-line store.
Simco is another on-line store.
New Era Factory Outlet has good prices on tuxedos (800-875-4959).