Abstract: A liquid dispenser. The dispenser includes a base structure, a plurality of cartridges releasably mounted to the base structure, and a valve fluidly coupled with an applicator head to allow continued contact with and selective deposition of the liquid to a product passing through a travel path between the cartridges. At least one of the cartridges is linked to the base structure through a variable coupling that is linearly responsive to changes in thickness or planarity of the product such that the applicator head automatically maintains constant contact with the product, regardless of such changes, without having to stop the dispenser or ancillary pieces of machinery. The cartridges are hand interchangeable such that liquid can be deposited on either an upper or lower surface of the product without requiring any tools to affect top-down or bottom-up deposition.