The flask pictured is the Walker flask and is also seen with the Dragoons. It does have an adjustable spout. The more common battle flags flask is not adjustable but you can change the spouts. You can buy 'sets' that well have several sizes. There are several styles of flasks with different designs embossed in the metal. The different designs are generally associated with certain revolvers. Never, never leave two flask alone in a draw, they well breed and before you know it you well have flask overload.
Fingers McGee said:C&Bs don't need to worry about embers in a chamber as long as you're not using paper cartridges.