Choir attire must be business casual while representing the choir at mass.

Uniform dress is required for all concerts, Confirmation, Christmas Eve and the Easter Vigil. 
Men: Black suits or tuxedos, white wing-tip tuxedo shirts and black (concert), red (Christmas) and white (Easter Vigil) bow ties.
Ladies: Black gowns are purchased from http://www.tuxedowholesaler.com/. The gown is the "Michaela" and is currently priced at $51.50.