Abstract: An apparatus that is an adjustable and selective dispensing system for dispensing at least two flowable materials, and into which can be inserted a set of cartridges containing the flowable materials. Each cartridge has a piston end and a metering end. Each cartridge includes a moveable piston at its piston end driven by compressed air pressure created by actuating a pump assembly also resident in the dispensing system. The dispensing system also contains a set of metering discs, one of which adjoins each of the cartridges at the metering end thereof, for selectively dispensing the flowable materials from the cartridges. There are a set of conduits adjacent each of the metering discs for providing a predetermined amount of the flowable materials to be dispensed. A metering control mechanism rotationally actuating the metering discs for controlling the flow of the flowable materials from each of the cartridges is also provided.