RBC21 APC RPLMNT BAT CART RBC21 BF500 Battery Technology's family of products grew to include over 1000 products for notebook computers, UPS units, cellular phones, camcorders, and Zip drives. BTI has become one of the leading manufacturers of batteries and accessories for notebook computers. By maintaining strict quality standards in production, as well as in sourcing, BTI is able to provide consistent, high capacity and durable batteries. This Replacement Battery Cartridge is designed for APC BF400C, APC BF500, APC BF500BB, APC BF500U.