When Bruce Wayne was thought dead, killed by Darkseid during the Final Crisis, Cassandra passes on the mantle of Batgirl to Stephanie Brown as part of Bruce's final instructions. Now without a superhero identity and seemingly estranging herself from the Bat Family, Cassandra eventually establishes herself in Hong Kong where Timothy Drake meets with her and hands her a new suit.
The suit uses the same colour scheme as her Batgirl suit, black and gold/yellow. Gone are the scalloped gloves; replaced with taloned gloves with white material wrapped around the forearms. Her boots are now split-toed tabi and her cape is wrapped around her neck, its edges shredded as ribbons.
Her mask is now a domino mask with bat-ears similar to that worn in Thomas Wayne's Batsuit. The mask exposes a large portion of her head and now leaves her hair, held back by a black hair band, free.
While not as large as they were on her Batgirl suit, her belt still possesses large pouches as well as a stylized Bat-buckle.
The first Black Bat to appear in DC comics was actually Barbara Hardy, a character fusion of Barbara Gordon (Batgirl) and Felicia Hardy (Black Cat), in the DC/Marvel Amalgamated Universe.
While Tim is shown handing her a suit, it is unknown wether it was this suit or Cassandra's original Batgirl suit and by extension it is unknown if Cassandra personally modified the suit to its current appearance.
The suit was first revealed on the cover of Red Robin #25.