Abstract: In a preferred embodiment, a system for dispensing semi-liquid materials in predetermined ratios, which system includes two cartridges having the same or selected different diameters, but proportional to the ratio of the materials to be dispensed, the cartridges being rigidly snapped together by interfitting male and female elements. In another aspect of the invention, there is provided a seal for a cartridge for dispensing semi-liquid material which seal includes a resilient wiping lip formed around the outer periphery of the seal which is forced against the inner surface of a cartridge by the flattening of the convex face of the seal. In a further aspect of the invention, there is provided a cartridge for dispensing semi-liquid material which cartridge includes grooves formed in the inner wall thereof extending inwardly a distance from the edge of the filling end thereof so that air may readily be expelled from the cartridge as the seal is inserted after filling of the cartridge.