Having amassed a larger fanbase this time around with, "A" and�"Mach", the�Rainbow girls are all set to wrap up their second single promotions with the November 11th episode of 'M! Countdown'. The girls have undoubtedly improved in leaps and bounds, in comparison to their debut "Gossip Girls" days. Check out their double-hit goodbye stage for "A" and "Mach" below!