Abstract: A vented output device for uniformly mixed liquid comprising a barrel defining a reservoir for containing the uniformly mixed liquid, and at least one vent channel extending from a first vent opening in fluid flow communication with an exterior of the device and second vent opening in fluid flow communication with the reservoir. A binary ink storage assembly includes multiple glass ampoules arranged in pairs, which are placed inside the barrel in parallel. The invention provides a reliable, simple and low-cost output device for solving the problem of not allowing the liquid to be uniformly mixed and output when a chemiluminescent marker or pen is activated.