A paint reservoir has an outlet connectable to a spray gun for transferring paint from the reservoir to the spray gun in use. The outlet is provided with a valve device for opening and closing the outlet to control flow of paint from the reservoir. The valve device has an outer sleeve axially slidable on a spout between a retracted position in which the outlet is closed and an extended position in which the outlet is open. The spout is integral with a lid of the reservoir and the sleeve is a push fit in an adapter for attaching the reservoir to a spray gun. The sleeve is provided with support arms for retainer hooks engageable with the adapter to releasably secure the reservoir to the spray gun.